I've heard that some Subaru models have 3 clocks in the view of the driver, all on the CAN bus, one being the nav and another being a remote display for the nav, and one that's just there, of which none sync to each others. I've looked up how it happened, and discovered that to just to add insult to injury, at least one uses a uC that has RTC feature but no XTAL pin for 32.768kHz or one of any sane base 2 divisions and uses CPU clock of 15MHz or something for it, so it just drifts away.
I don't understand how Subaru stays in the business. Just how. It's a 4 digit time. Just broadcast it on CAN. Why not.
Also: a lot of these older, completely rectangular sat nav units actually follow what is colloqially known as "2DIN" standards. (cheap import Amazon)Aftermarket units are available and those can be swapped in with just a bit of work. That's what most people do when they have issues with the stock unit installed for their markets.
My smart fortwo has two clocks, one on the radio, one in the driver’s dashboard;
Both go wrong over time, but both in two different directions, so the trick is to calculate the „average“ between both, and you end up with roughly the correct time.
I've heard that the redesigned 2026 Outback has a much nicer interior. Lots of physical buttons and supposedly more stable infotainment software.
We've been pretty happy with our 2020 Outback so far (bought it just before the chip shortage). My only complaint is the stability of the infotainment software. The big portrait screen is actually quite nice, and with CarPlay I don't really care about the rest of UI and software. Except that the stupid thing just crashes all the time.
yeah, I've heard that too - I have a new forester - it's def slow/finicky
maybe I'll get a outback instead next time, they are kind of the same to me though the hybrid on the forester I have def makes it a more pleasant less CVT'y ride...
I'm hoping they bring the new Outback design (both exterior and interior) to the Ascent. The 2027 Ascent is already out and unfortunately it's the same old styling and infotainment.
And their engines have struggled with gasket issues and oil consumption for a long time. People here love the AWD, though (my state enshrines AWD as a special class in law, artificially driving some demand).
Of the EJ20 just to keep it easy to play with the blocks without needing a modified type certs right? None of my business but they seem to be a bit unserious somewhat within bounds of a car company.
In western Washington State everything is on a hill and it feels as if the road is always wet all the time due to rain. Subaru is the most popular car brand in the whole state because it handles these conditions well.
Wet all the time isn’t a serious loss of traction. Wet after a dry spell is, and everyone there forgets it every time. You will have delays on the highways due to wrecks.
Nobody has the slightest clue how to deal with ice.
I had a luxury car from 2001 where the time could not be manually changed, only set to specific time zones. Of course, all the time zone rules had long diverged from its rule set, and it had to be changed four times a year to show the correct time.
This car also inexplicably forced you to manually choose a country, and then a time zone, despite having a GPS that already knew exactly where you were and already had chosen a previous time zone.
Carplay is nice but I would have settled for a non-luxury "clock set" button.
My 2019 Subaru has a red 7-segment LED clock below the touchscreen that has 2 physical buttons right there that change the hour and minute. It's a luxury I don't think I'll soon take for granted. I changed my battery recently (the original OEM battery finally got too tired), so I've set my clock twice in the last week, taking about 10 seconds and 1/2 second to accomplish respectively.
I can't wait until folks start pulling firmware out of head units, using AI to remove the crap, and putting it back in (akin to the TV revolution happening now)
(in NZ) I have a 2005 import from Japan with time set by GPS, but apparently no way of changing the time zone away from Japan. The navigation still thinks I'm in Japan too but randomly flying around at high speeds too - even the compass calibration is way off. I too would rather have a manual clock set.
> Carplay is nice but I would have settled for a non-luxury "clock set" button.
The clock set button is obviously the right solution, but this is actually why I demand CarPlay on any infotainment system in a car. I don't trust the manufacturers will keep it up to date, but I know my phone software will be updated/updateable/replaceable.
Yep. I didn't get into it in the article, but in reality the previous owner had already (accidentally) thrown the SD card in the trash, and was pretty much asking me if they want me for them to go digging through their trash to find it, and I told them not to worry about it.
I’m a little confused by the description of that interaction - why wouldn’t you take the SD card? Did they want to charge extra for it? Seems like even a 10 year old map (plus apparently other functionality) is something you’d want.
In any case, glad it took you on the wild goose chase that led to the write up!
I started using an "engineering notebook" for things like that. They are called other things in other lines of work or school (lab notebook, captain's log, ...). In an actual engineering notebook, you would use a sewn binding where you can't add or remove pages, the pages are numbered, you have an index in the front, entries are made in strictly chronological order, you'd have someone else witness and sign pages, draw a diagonal line across empty areas so you can't remove things, only cross things out with a single line, etc. All that because you might need to prove you invented something and other legal CYA reasons. Most of these requirements, you don't need for personal projects, though. But the things that are useful: keeping track of projects, what settings you've tried, what the results were, and so on. That way you don't have to reproduce it from scratch again later. "What settings did I need use to create the gerber files in kicad for manufacturing? How did I set ___ in the oscilloscope? What parts did I use to make that thing? What things did I wish I had checked last time? Where did I put those files?" You can also print things out and tape them in for reference.
I just use composition notebooks which are like $1-$5 depending on the quality, store, sales, etc. That's also what we used as a lab notebook in chemistry class when I was in high school, which follows a similar discipline, so to me it's fitting.
The whole article is ludicrous. Why do you even need a car with an SD card slot in order to change the time? I reset all of my clocks this weekend and I don't even have a car.
> Why do you even need a car with an SD card slot in order to change the time?
The idea was that time came from GPS and you had a SD card with the update files for the maps and the current tzdata information. Timezones worldwide change ridiculously often and tying that together with the regular map updates makes sense.
Remember these things are from an era where smartphones were barely a thing and so was mobile phone connectivity in cars.
My car came with a cheap low-quality aftermarket combination car stereo and GPS. It would only play music from discs (no USB support), didn’t even support variable bitrate MP3s, and the GPS didn’t know the car’s location half the time.
I finally replaced the head unit with a plastic bracket and a standard old school in-dash stereo system. Much nicer setup.
It’s the cars which can’t have their head unit replaced with a simple stereo which worry me.
> It’s the cars which can’t have their head unit replaced with a simple stereo which worry me.
I agree. There's a lot of room for innovation, consumer choice, and competition that was previously guaranteed to be available in those one or two DIN units of space.
I haven't seen them present in any new car I've looked at in nearly ten years, but they were in every car I saw from the 50 years prior.
Denso head units for Toyotas can play MP3s, but the order of the files is when when they were copied to the SD drive. And you can't sort them any other way.
The counter argument to that is well designed modern cars have great info-tainment systems which get regular updates. My Tesla gets regular software updates, has upgradable hardware, and won't be subject to these kinds of issues for decades. Old cars encouraged exchanging and needed aftermarket parts because they didn't care or try, so the products were low-quality and often failed.
> My Tesla gets regular software updates, has upgradable hardware, and won't be subject to these kinds of issues for decades.
Teslas from four years ago with Intel Atom processors and HW3 are already getting different and lesser updates than new Teslas, without any hardware upgrade plan in place.
A Tesla you buy right now is running HW4 which is inferior to current Cybercabs and HW5 has already been announced.
Legacy automakers are still using the "ship it and forget it" approach. If I want my 2023 Hyundai to have the same features as a 2025 (manual battery preconditioning, Google Maps directions on HUD, wireless Android Auto, etc), I need to root the head unit and install a bunch of vibe coded packages from randos on GitHub.
Although to be fair the vibecoded packages are probably higher quality than what Hyundai would've shipped.
> well designed modern cars have great info-tainment systems which get regular updates. My Tesla gets regular software updates
And tracks you everwhere you go, resulting in that data being available to hackers, marketers, and any sleazeball that wants to extort you by suing you.
Not unique to tesla, of course, but a property of all those 'well designed modern cars'.
My 2014 vehicle stopped updating it's time automatically a few years ago. I think some cellular technology was phased out or perhaps the cellular contract GM had for vehicle connectivity expired.
Either way I just manually set the time twice a year now - I guess I'm thankful it still has that option.
When I was playing around with the radio in my girlfriends vehicle there was no option to set manually on the clock screen. Seems like a pretty shortsighted move to not allow that.
Older versions of the GM OnStar hardware used 2G cellular radios and carriers have decommissioned those networks. Adapters are available for some vehicles to use newer networks.
Considering that OnStar spies on you even if you don't subscribe to the service it's much better to just leave it broken, or even to actively disconnect it in newer vesicles.
It seems absurd to me that cars needs a cellular connection to automatically set time, meanwhile 10$ clocks can get the time correctly from the radio signal that are broadcasted. More insulting the fact that the car itself has an FM and also an AM tuner that are capable of receiving time signal and decoding them while the radio is not in use. And that modern cars that use digital radio (DAB) have a standard to get the time. Come on, car infotainment is so outdated...
As an Arizona resident, my recent Honda CRV's clock is off by an hour for half the year. Since usually the carplay display overrides the clock, it's no big deal, but it cracks me up that, despite being a professional programmer, I have yet to figure out how to set it correctly
The difficulty of setting a VCR's clock was a meme in the 1990s, and I can attest, justifiably so.
But at least it was possible. The clock setting being impossible without a proprietary and easily lost or destroyed SD card is pretty good, but we can do better. It could be just impossible to fix a wrong clock. Truly that would be the apotheosis of user unfriendly design.
My very technical and hands on father used to have us set the VCR clock, the controls were in a tiny compartment under a flap that required either small fingers, or very careful manipulation with the point of a protractor or something.
We went from difficult to manipulate buttons through to multi-function buttons where controls get hidden through some incomprehensible maze of menu options, to now where it sometimes feels lucky if you even get an option to manually set the time at all.
I'm reminded of an old commercial depicting kids taunting another kid by asking "What time is it at Billy's house? 12 O'Clock! 12 O'Clock! 12 O'Clock!" Might have been a Blockbuster commercial? I can't remember.
Oh man, this reminds me of an episode of a show I watched when I was a kid in the 90s, where the running joke was all the characters, at different points, saying something like "I tried setting up the VCR to record it, but every time I press the button the number 12:00 starts flashing on the screen and I panic." I haven't been able to find it again. I think it was https://en.wikipedia.org/wiki/Mother_Goose_and_Grimm_(TV_ser...
In 1974 when I was an medical intern at Los Angeles County-University of Southern California Hospital, ALL the round analog wall clocks with hands in all 26 operating rooms were correct six months a year: there was NO provision for automatically advancing/moving them back when DST started/ended, nor did anyone do it manually.
I was told by our school electrician that long ago the clocks were adjusted by the power company. So around 2am DST they would either send power at 59Hz* to fall back or 61Hz* to spring forward. This was from the era when power grids were separate and analog. With newer national grid-tie it might not even be possible to do now.
> I was told by our school electrician that long ago the clocks were adjusted by the power company. So around 2am DST they would either send power at 59Hz* to fall back or 61Hz* to spring forward. This was from the era when power grids were separate and analog.
That wouldn't have worked.
Grid-tied synchronous clocks (https://en.wikipedia.org/wiki/Electric_clock) were once ubiquitous and did derive their timekeeping stability from the grid frequency, but that is only suitable for keeping time once set. It works because electric grids are frequency-controlled and stabilized, where deviations from the reference frequency are corrected over long intervals.
In principle you could send power at 59 or 61Hz to adjust these clocks, but there are two problems:
1. The grid frequency isn't arbitrary, it's also directly coupled to the rotary inertia of every turbine that powers the grid. This is why power fluctuations cause frequency changes: temporary oversupply or undersupply causes these turbines to slow down or speed up respectively, using their inertia as power storage. Potentially screwing up every other piece of mechanical equipment tied to the grid for the sake of clock changes is... a poor optimization.
2. A one-Hertz difference isn't enough to change the clocks in a timely way. To change time by an hour you need to gain or lose 3600 * 60 = 216k cycles, but a 1Hz change gains or loses one cycle per second. It'd take about 2.5 days to complete a one-hour change via this mechanism.
I don’t know about that, but I was told by someone who worked at a power generation plant in the 1970s that they had a clock in the plant, that they would compare to the time broadcast on the radio frequency that carried the official time, and any time it diverged they would slightly adjust the frequency of the alternating current until it matched.
I was a kid but I do know the clocks in my elementary, middle, and high school were accurate. Near end of day, we would impatiently stare at the clock waiting for the release bell. Being a public school, the clocks were bolted securely to the wall. Being little shits, students would probably steal them if they could, LOL. So how did they keep 100s of clocks on time? I asked and was told by the school maintenance that it was done through power.
I remember in my elementary school the clocks were all synchronized to a system somewhere, presumably in the head office. The day after going back to school after a DST change the clocks would all be off by an hour and sometime in that morning they would all suddenly freeze, then fast forward or rewind an hour and then restart. In retrospect it is amusing that whomever was in charge of updating the clocks didn't do it when they first got in but waited until the school day had started.
What are the odds they did have a centralized system for setting the clocks, but nobody knew how to operate it or cared enough to find out? Maybe someone set a password and then lost it. And of course if you have a centralized system it means you can't manually fix the individual clocks.
I worked in a Network Operations Center in the early 1990s, and there was a large projection display with four other monitors around it. Across the top were four round analog clocks, representing the time zones of the United States. I was one of four operators, all in our 20s.
So, Daylight Savings Time ended, and the early-morning operator had all the clocks set by the time I arrived, and the third operator came in, looked at them, and said "Great! So, did you take all four of them down and adjust the time individually?" "Yeah" "Didn't think about taking one off the end, adjusting it, and moving the others down the row?" *facepalm*
A design rule for the display of any appliance with a clock: It must be possible to remove or hide the clock. I don’t need 10 devices to keep track of time for me.
Yes, please. I don't want a clock on my microwave, or my oven. If I'm not interacting with it, it should produce zero light.
(Some people use oven features that involve knowing an absolute time, such as "turn on at this time". That seems to be the uncommon case, and meanwhile everyone has to deal with a clock that's rarely right.)
Eh, if you only have a clock on only the microwave or oven then you lose access to the current time when you're cooking something or convert it over to timer mode. Having some redundancy isn't a bad thing in this instance.
Or simply have a dedicated clock in there and turn off the display on all of the appliances.
There should be two kinds of devices in my home: those allowed to connect to the Internet and keep their time up to date, and those that are not allowed to care what time it is. My microwave and my oven are in the latter category.
Best they can do is blinking "12:00". Actually I encountered a kitchen appliance doing almost the opposite, after power off/on it didn't function before confirming any time.
Amen to that, I have a pair of built-in IKEAs, a microwave and convection oven, both with clocks when they're idle. But of course they're separate devices so they drift separately, which is obnoxious-looking. Happily the microwave did have a hidden setting to just display - - - - instead of the clock (though for no apparent reason the convection oven does not have that option, sigh).
It's been awhile since I looked, but for at least some Mazda's you can use a usb stick with mp3s that have certain names to get access to the linux system.
I never understood why car companies don't put more effort and resources into their MMI systems. Audi is a big offender. I've never seen a more thoughtfully designed car with an MMI interface that's more frustrating and buggy.
First is to bring the hardware and software design in-house. Except auto companies don't do well at software, they're used to letting OEM vendors write the engine control firmware etc etc. There's also the problem of the very long design cycles in car manufacturing. The new car platform being built today started its design four to five years ago. And that's when the hardware was locked down.
Volvo's platform was so old at launch that they threw in the towel and are now offering to upgrade your hardware if you complain hard enough.
The other choice is to shop it all out to a consulting firm or OEM vendor. Then you have cultural conflicts between the car maker and the programmers, communication overhead, choice of hardware conflicts, etc. And you know it's going to be shopped out to the cheapest bidder. And you're still at the mercy of launching with hardware that's way older than the smartphone in the driver's pocket.
Isn't it because the nav feature is market specific? People generally don't seem to like nav software brought in from different continents, across the planet.
I got a new samsung smart tv in April and never connected it to the internet. Just noticed (likely because if the DST change) that the date and time was all wrong when it turns on. Could not unnotice it. I was very pleasantly surprised I could manually set it and no internet was required. I expected to be annoyed at it forever or to go down a rabbit hole like this and fail.
I was just wondering the same thing for a 2013 Honda Civic - has the screen's (the "head unit"?) firmware been fully dumped and reverse engineered?
How realistic would it be to run fully custom firmware there, and even communicate over usb - for example, if I had a pi running in the car, and it used the usb connection to show things on the built-in display?
I'd love to pwn the head unit in my 2014 Honda CR-V just so I can stop it from sending a "Play" command every time a phone associates with the Bluetooth and the audio system was left "on".
I also have a 2014 CR-V and I hate this too. But even moreso, I hate that there isn't a play/pause button at all. If I need to stop audio (e.g. pulling up to a drivethru, or starting a conversation), I gotta hit the phone. Heaven forbid I'm playing a CD, nothing I can do at that point.
Putting up a bug bounty of "ordering you a pizza" if anyone tackles this!
Had a Chevy that was extremely obnoxious about this. If it was playing over USB it absolutely would not allow it to stop. Hitting pause on the phone would have the car immediately hit play to restart it.
It's probably easier to just buy an aftermarket head unit. The only thing you'll need to confirm is that it supports features you care about e.g. steering wheel controls.
Okay, this was gratifying to read, but ... can't you wedge CarPlay onto this thing? I'd want a victory lap with root doing at least something. Bad apple on car boot, there's lots of options here!
Yeah, I'll keep working on this to get it to do more stuff that's at least a little bit more useful, if not just a better UI that isn't 90% a useless "No maps found" screen. It's more complicated than it might initially seem because they actually have a kernel module blocking me from mounting non-signed partitions as exec, so I'll need to work around that.
I'll probably post a follow up if I get anywhere with this!
Pretty awesome write up to explain their journey in it all.
I suspect a bunch of car head units will face new problems in the spring when many Canadian provinces will no longer change their clocks. The units won't get updated DST rules.
my skoda simply has an entry in the menu: DST? which puts the clock one hour ahead or behind.
This posts remind me that when i will be in the market for a new van i will have to decide to get the trafic or the vivaro, solely on the head unit they use (renault ones have had incredibly stupid design decisions for years, on ergonomics alone, even more in firmware)
I wish someone would jailbreak the Nissan Leaf (MY2018) head unit. Every time I turn on the car, it shows a EULA asking if Nissan can please collect every detail of my car at all times and sell it to whoever asks.
Every. Time.
Even if I beat my head with hammers to think like a lawyer, I can't imagine how it would be necessary to ask constantly. Doesn't matter if I accept or decline, it still asks again.
I hate to laugh but the thought of you constantly rejecting the EULA for weeks on end, to finally give in one day, press accept and come to terms with it, only to get in the next time and have it pop up.
I can only imagine the amount of expletives that were said at that exact moment.
8 inches or more of dashboard real estate to display "maps not found", "don't get distracted" warning, terms and conditions, and blinking "12:00". Having had rented a fair share of subcompact and compact cars in half dozen of countries, the car navigation was updated and working exactly only once.
> The system had DRM checks which rejected SD cards without the correct CID (a unique ID burned into the card) and files with signatures based on that specific CID, so I couldn't even copy the files to a blank SD card.
FWIW, there are grey market sites that will sell you an SD burned with a custom CID so you can clone an SD card with this kind of copy protection. It sounds like in this case maybe he could've gotten away with an empty maps card + menu definitions file.
I've heard that some Subaru models have 3 clocks in the view of the driver, all on the CAN bus, one being the nav and another being a remote display for the nav, and one that's just there, of which none sync to each others. I've looked up how it happened, and discovered that to just to add insult to injury, at least one uses a uC that has RTC feature but no XTAL pin for 32.768kHz or one of any sane base 2 divisions and uses CPU clock of 15MHz or something for it, so it just drifts away.
I don't understand how Subaru stays in the business. Just how. It's a 4 digit time. Just broadcast it on CAN. Why not.
Also: a lot of these older, completely rectangular sat nav units actually follow what is colloqially known as "2DIN" standards. (cheap import Amazon)Aftermarket units are available and those can be swapped in with just a bit of work. That's what most people do when they have issues with the stock unit installed for their markets.
My smart fortwo has two clocks, one on the radio, one in the driver’s dashboard;
Both go wrong over time, but both in two different directions, so the trick is to calculate the „average“ between both, and you end up with roughly the correct time.
subaru infotainment is junk but they are a good deal for a safe car
I've heard that the redesigned 2026 Outback has a much nicer interior. Lots of physical buttons and supposedly more stable infotainment software.
We've been pretty happy with our 2020 Outback so far (bought it just before the chip shortage). My only complaint is the stability of the infotainment software. The big portrait screen is actually quite nice, and with CarPlay I don't really care about the rest of UI and software. Except that the stupid thing just crashes all the time.
yeah, I've heard that too - I have a new forester - it's def slow/finicky
maybe I'll get a outback instead next time, they are kind of the same to me though the hybrid on the forester I have def makes it a more pleasant less CVT'y ride...
I'm hoping they bring the new Outback design (both exterior and interior) to the Ascent. The 2027 Ascent is already out and unfortunately it's the same old styling and infotainment.
I also only use Android Auto, and plugging my phone in updates all the clocks automatically
And their engines have struggled with gasket issues and oil consumption for a long time. People here love the AWD, though (my state enshrines AWD as a special class in law, artificially driving some demand).
That makes sense. AWD handling is so much better in winter conditions that I feel it has to make it less likely to crash.
Of the EJ20 just to keep it easy to play with the blocks without needing a modified type certs right? None of my business but they seem to be a bit unserious somewhat within bounds of a car company.
What benefits do you get from having an AWD car in your state? Tax treatment?
Just the benefit of driving AWD is enough for me. It's hard to go back...
In western Washington State everything is on a hill and it feels as if the road is always wet all the time due to rain. Subaru is the most popular car brand in the whole state because it handles these conditions well.
Wet all the time isn’t a serious loss of traction. Wet after a dry spell is, and everyone there forgets it every time. You will have delays on the highways due to wrecks.
Nobody has the slightest clue how to deal with ice.
With AWD, the tire requirements when it’s snowing in the mountains are more relaxed compared to 2wd vehicles.
However every time one of your tires goes bad you have to replace all four.
This is a niche problem but I live in Colorado
Mountains.
I had a luxury car from 2001 where the time could not be manually changed, only set to specific time zones. Of course, all the time zone rules had long diverged from its rule set, and it had to be changed four times a year to show the correct time.
This car also inexplicably forced you to manually choose a country, and then a time zone, despite having a GPS that already knew exactly where you were and already had chosen a previous time zone.
Carplay is nice but I would have settled for a non-luxury "clock set" button.
My 2025 Toyota has two clocks, one from Toyota, one from Android auto.
The Toyota one requires selling your driving data to insurance companies.to update the tzoffset based on location.
And so two clocks on the dashboard are off this week until I can remember where the dst adjustment is in the settings.
My 2019 Subaru has a red 7-segment LED clock below the touchscreen that has 2 physical buttons right there that change the hour and minute. It's a luxury I don't think I'll soon take for granted. I changed my battery recently (the original OEM battery finally got too tired), so I've set my clock twice in the last week, taking about 10 seconds and 1/2 second to accomplish respectively.
I can't wait until folks start pulling firmware out of head units, using AI to remove the crap, and putting it back in (akin to the TV revolution happening now)
Open AI put a stop to the TV hacking. I can not wait until memory gets cheap again and we could run large models _comfortably_ at home.
Yes, I don't expect my software tools to selectively fail when they determine that my command puts another company's business model at risk.
(in NZ) I have a 2005 import from Japan with time set by GPS, but apparently no way of changing the time zone away from Japan. The navigation still thinks I'm in Japan too but randomly flying around at high speeds too - even the compass calibration is way off. I too would rather have a manual clock set.
> Carplay is nice but I would have settled for a non-luxury "clock set" button.
The clock set button is obviously the right solution, but this is actually why I demand CarPlay on any infotainment system in a car. I don't trust the manufacturers will keep it up to date, but I know my phone software will be updated/updateable/replaceable.
Honestly I’ll just wear a watch.
I would have taped a $5 casio watch clone on the dashboard were the clock is supposed to be shown.
Could be planned obsolescence.
Awesome write up. Love it. And good thing you documented it, since in half a year you'll need it again.
My takeaway: You should have just gotten the SD card and trusted the previous owner. Sometimes "simple users" do know. ^^
Yep. I didn't get into it in the article, but in reality the previous owner had already (accidentally) thrown the SD card in the trash, and was pretty much asking me if they want me for them to go digging through their trash to find it, and I told them not to worry about it.
“No worries, I’ll hit HN’s front page instead” - much more fun!
Why did the previous owner ever remove the card in the first place if they knew it broke things?
Because if OP didn't want the card, then the card could be sold on ebay for 60 euros.
That's kind of you :-)
Nice writeup. But IIUC you can change it so that it automatically updates the time every 6 months?
I’m a little confused by the description of that interaction - why wouldn’t you take the SD card? Did they want to charge extra for it? Seems like even a 10 year old map (plus apparently other functionality) is something you’d want.
In any case, glad it took you on the wild goose chase that led to the write up!
> And good thing you documented it, since in half a year you'll need it again.
Man this is too real for personal projects. I really need to write down my findings and thoughts more for future me.
I started using an "engineering notebook" for things like that. They are called other things in other lines of work or school (lab notebook, captain's log, ...). In an actual engineering notebook, you would use a sewn binding where you can't add or remove pages, the pages are numbered, you have an index in the front, entries are made in strictly chronological order, you'd have someone else witness and sign pages, draw a diagonal line across empty areas so you can't remove things, only cross things out with a single line, etc. All that because you might need to prove you invented something and other legal CYA reasons. Most of these requirements, you don't need for personal projects, though. But the things that are useful: keeping track of projects, what settings you've tried, what the results were, and so on. That way you don't have to reproduce it from scratch again later. "What settings did I need use to create the gerber files in kicad for manufacturing? How did I set ___ in the oscilloscope? What parts did I use to make that thing? What things did I wish I had checked last time? Where did I put those files?" You can also print things out and tape them in for reference.
I love the ergonomics of hard bound engineering notebooks. The cost is more than I'm willing to pay for the pedestrian kind of notes I take, though.
I got a few of them, partially-used, from a canceled project and I really enjoyed using and carrying them.
I just use composition notebooks which are like $1-$5 depending on the quality, store, sales, etc. That's also what we used as a lab notebook in chemistry class when I was in high school, which follows a similar discipline, so to me it's fitting.
MEMORY.md is your friend.
I’d rather read my own internal wiki tbh
That’s the part I don’t get: just take the damned card, you never know. Worst case: hey, free SD card!
Add to falsehoods programmers believe about time:
It can be changed without the SD card in the car radio.
The whole article is ludicrous. Why do you even need a car with an SD card slot in order to change the time? I reset all of my clocks this weekend and I don't even have a car.
Well, they needed a car to change the time in "Back to the future".
This question was certainly asked during a meeting 30 years ago and the answer was "don't worry about it".
> Why do you even need a car with an SD card slot in order to change the time?
The idea was that time came from GPS and you had a SD card with the update files for the maps and the current tzdata information. Timezones worldwide change ridiculously often and tying that together with the regular map updates makes sense.
Remember these things are from an era where smartphones were barely a thing and so was mobile phone connectivity in cars.
Whoosh
My car came with a cheap low-quality aftermarket combination car stereo and GPS. It would only play music from discs (no USB support), didn’t even support variable bitrate MP3s, and the GPS didn’t know the car’s location half the time.
I finally replaced the head unit with a plastic bracket and a standard old school in-dash stereo system. Much nicer setup.
It’s the cars which can’t have their head unit replaced with a simple stereo which worry me.
> It’s the cars which can’t have their head unit replaced with a simple stereo which worry me.
I agree. There's a lot of room for innovation, consumer choice, and competition that was previously guaranteed to be available in those one or two DIN units of space.
I haven't seen them present in any new car I've looked at in nearly ten years, but they were in every car I saw from the 50 years prior.
Denso head units for Toyotas can play MP3s, but the order of the files is when when they were copied to the SD drive. And you can't sort them any other way.
The counter argument to that is well designed modern cars have great info-tainment systems which get regular updates. My Tesla gets regular software updates, has upgradable hardware, and won't be subject to these kinds of issues for decades. Old cars encouraged exchanging and needed aftermarket parts because they didn't care or try, so the products were low-quality and often failed.
> My Tesla gets regular software updates, has upgradable hardware, and won't be subject to these kinds of issues for decades.
Teslas from four years ago with Intel Atom processors and HW3 are already getting different and lesser updates than new Teslas, without any hardware upgrade plan in place.
A Tesla you buy right now is running HW4 which is inferior to current Cybercabs and HW5 has already been announced.
Legacy automakers are still using the "ship it and forget it" approach. If I want my 2023 Hyundai to have the same features as a 2025 (manual battery preconditioning, Google Maps directions on HUD, wireless Android Auto, etc), I need to root the head unit and install a bunch of vibe coded packages from randos on GitHub.
Although to be fair the vibecoded packages are probably higher quality than what Hyundai would've shipped.
> well designed modern cars have great info-tainment systems which get regular updates. My Tesla gets regular software updates
And tracks you everwhere you go, resulting in that data being available to hackers, marketers, and any sleazeball that wants to extort you by suing you.
Not unique to tesla, of course, but a property of all those 'well designed modern cars'.
My 2014 vehicle stopped updating it's time automatically a few years ago. I think some cellular technology was phased out or perhaps the cellular contract GM had for vehicle connectivity expired.
Either way I just manually set the time twice a year now - I guess I'm thankful it still has that option.
When I was playing around with the radio in my girlfriends vehicle there was no option to set manually on the clock screen. Seems like a pretty shortsighted move to not allow that.
> the cellular contract GM had for vehicle connectivity expired
2022, I got a letter saying that my car's crash response SOS system will stop working because FCC is retiring the 3G spectrum it is using.
The car clock however is synced to the GPS instead.
If GM used NTP instead of GPS, then it makes sense that it stopped working arbitrarily around 2022.
Older versions of the GM OnStar hardware used 2G cellular radios and carriers have decommissioned those networks. Adapters are available for some vehicles to use newer networks.
https://www.onstar.com/support/faq/2g-network-sunset
Considering that OnStar spies on you even if you don't subscribe to the service it's much better to just leave it broken, or even to actively disconnect it in newer vesicles.
In 2019 there was a GPS week number rollover, another possible cause.
https://en.wikipedia.org/wiki/GPS_week_number_rollover
It seems absurd to me that cars needs a cellular connection to automatically set time, meanwhile 10$ clocks can get the time correctly from the radio signal that are broadcasted. More insulting the fact that the car itself has an FM and also an AM tuner that are capable of receiving time signal and decoding them while the radio is not in use. And that modern cars that use digital radio (DAB) have a standard to get the time. Come on, car infotainment is so outdated...
Apt time to share this video about jailbreaking a car's navigation system to get its PIN to unlock it.
https://www.youtube.com/watch?v=oC6AiLqjtRg
As an Arizona resident, my recent Honda CRV's clock is off by an hour for half the year. Since usually the carplay display overrides the clock, it's no big deal, but it cracks me up that, despite being a professional programmer, I have yet to figure out how to set it correctly
The difficulty of setting a VCR's clock was a meme in the 1990s, and I can attest, justifiably so.
But at least it was possible. The clock setting being impossible without a proprietary and easily lost or destroyed SD card is pretty good, but we can do better. It could be just impossible to fix a wrong clock. Truly that would be the apotheosis of user unfriendly design.
My very technical and hands on father used to have us set the VCR clock, the controls were in a tiny compartment under a flap that required either small fingers, or very careful manipulation with the point of a protractor or something.
We went from difficult to manipulate buttons through to multi-function buttons where controls get hidden through some incomprehensible maze of menu options, to now where it sometimes feels lucky if you even get an option to manually set the time at all.
I'm reminded of an old commercial depicting kids taunting another kid by asking "What time is it at Billy's house? 12 O'Clock! 12 O'Clock! 12 O'Clock!" Might have been a Blockbuster commercial? I can't remember.
Oh man, this reminds me of an episode of a show I watched when I was a kid in the 90s, where the running joke was all the characters, at different points, saying something like "I tried setting up the VCR to record it, but every time I press the button the number 12:00 starts flashing on the screen and I panic." I haven't been able to find it again. I think it was https://en.wikipedia.org/wiki/Mother_Goose_and_Grimm_(TV_ser...
In 1974 when I was an medical intern at Los Angeles County-University of Southern California Hospital, ALL the round analog wall clocks with hands in all 26 operating rooms were correct six months a year: there was NO provision for automatically advancing/moving them back when DST started/ended, nor did anyone do it manually.
I was told by our school electrician that long ago the clocks were adjusted by the power company. So around 2am DST they would either send power at 59Hz* to fall back or 61Hz* to spring forward. This was from the era when power grids were separate and analog. With newer national grid-tie it might not even be possible to do now.
> I was told by our school electrician that long ago the clocks were adjusted by the power company. So around 2am DST they would either send power at 59Hz* to fall back or 61Hz* to spring forward. This was from the era when power grids were separate and analog.
That wouldn't have worked.
Grid-tied synchronous clocks (https://en.wikipedia.org/wiki/Electric_clock) were once ubiquitous and did derive their timekeeping stability from the grid frequency, but that is only suitable for keeping time once set. It works because electric grids are frequency-controlled and stabilized, where deviations from the reference frequency are corrected over long intervals.
In principle you could send power at 59 or 61Hz to adjust these clocks, but there are two problems:
1. The grid frequency isn't arbitrary, it's also directly coupled to the rotary inertia of every turbine that powers the grid. This is why power fluctuations cause frequency changes: temporary oversupply or undersupply causes these turbines to slow down or speed up respectively, using their inertia as power storage. Potentially screwing up every other piece of mechanical equipment tied to the grid for the sake of clock changes is... a poor optimization.
2. A one-Hertz difference isn't enough to change the clocks in a timely way. To change time by an hour you need to gain or lose 3600 * 60 = 216k cycles, but a 1Hz change gains or loses one cycle per second. It'd take about 2.5 days to complete a one-hour change via this mechanism.
I don’t know about that, but I was told by someone who worked at a power generation plant in the 1970s that they had a clock in the plant, that they would compare to the time broadcast on the radio frequency that carried the official time, and any time it diverged they would slightly adjust the frequency of the alternating current until it matched.
I was a kid but I do know the clocks in my elementary, middle, and high school were accurate. Near end of day, we would impatiently stare at the clock waiting for the release bell. Being a public school, the clocks were bolted securely to the wall. Being little shits, students would probably steal them if they could, LOL. So how did they keep 100s of clocks on time? I asked and was told by the school maintenance that it was done through power.
I remember in my elementary school the clocks were all synchronized to a system somewhere, presumably in the head office. The day after going back to school after a DST change the clocks would all be off by an hour and sometime in that morning they would all suddenly freeze, then fast forward or rewind an hour and then restart. In retrospect it is amusing that whomever was in charge of updating the clocks didn't do it when they first got in but waited until the school day had started.
It's crazy they didn't have a centralized clock system in a facility like that. What a thing to scrimp on.
What are the odds they did have a centralized system for setting the clocks, but nobody knew how to operate it or cared enough to find out? Maybe someone set a password and then lost it. And of course if you have a centralized system it means you can't manually fix the individual clocks.
I'd laugh whenever I looked up and saw the wrong time....
I worked in a Network Operations Center in the early 1990s, and there was a large projection display with four other monitors around it. Across the top were four round analog clocks, representing the time zones of the United States. I was one of four operators, all in our 20s.
So, Daylight Savings Time ended, and the early-morning operator had all the clocks set by the time I arrived, and the third operator came in, looked at them, and said "Great! So, did you take all four of them down and adjust the time individually?" "Yeah" "Didn't think about taking one off the end, adjusting it, and moving the others down the row?" *facepalm*
A design rule for the display of any appliance with a clock: It must be possible to remove or hide the clock. I don’t need 10 devices to keep track of time for me.
Yes, please. I don't want a clock on my microwave, or my oven. If I'm not interacting with it, it should produce zero light.
(Some people use oven features that involve knowing an absolute time, such as "turn on at this time". That seems to be the uncommon case, and meanwhile everyone has to deal with a clock that's rarely right.)
Eh, if you only have a clock on only the microwave or oven then you lose access to the current time when you're cooking something or convert it over to timer mode. Having some redundancy isn't a bad thing in this instance.
Or simply have a dedicated clock in there and turn off the display on all of the appliances.
There should be two kinds of devices in my home: those allowed to connect to the Internet and keep their time up to date, and those that are not allowed to care what time it is. My microwave and my oven are in the latter category.
> such as "turn on at this time". That seems to be the uncommon case
Indeed. "Please create fire hazard exactly at this hour when I'll not have time to do it personally".
Best they can do is blinking "12:00". Actually I encountered a kitchen appliance doing almost the opposite, after power off/on it didn't function before confirming any time.
Amen to that, I have a pair of built-in IKEAs, a microwave and convection oven, both with clocks when they're idle. But of course they're separate devices so they drift separately, which is obnoxious-looking. Happily the microwave did have a hidden setting to just display - - - - instead of the clock (though for no apparent reason the convection oven does not have that option, sigh).
For certain model years of nissan, there's this, btw
https://github.com/ea/bosch_headunit_root
If anyone feels like using that access to throw some tokens at various systems.
It's been awhile since I looked, but for at least some Mazda's you can use a usb stick with mp3s that have certain names to get access to the linux system.
I never understood why car companies don't put more effort and resources into their MMI systems. Audi is a big offender. I've never seen a more thoughtfully designed car with an MMI interface that's more frustrating and buggy.
There are two paths and both don't work anymore.
First is to bring the hardware and software design in-house. Except auto companies don't do well at software, they're used to letting OEM vendors write the engine control firmware etc etc. There's also the problem of the very long design cycles in car manufacturing. The new car platform being built today started its design four to five years ago. And that's when the hardware was locked down.
Volvo's platform was so old at launch that they threw in the towel and are now offering to upgrade your hardware if you complain hard enough.
The other choice is to shop it all out to a consulting firm or OEM vendor. Then you have cultural conflicts between the car maker and the programmers, communication overhead, choice of hardware conflicts, etc. And you know it's going to be shopped out to the cheapest bidder. And you're still at the mercy of launching with hardware that's way older than the smartphone in the driver's pocket.
Auto companies almost all do their own engines. They may trade but they make their own. That includes software.
TDD was an invention of Chrysler.
Even companies with betterish interfaces screw this up.
My Model 3 is showing the wrong time and this requires an OS update to fix.
Suffice to say I would prefer an option to update it myself.
https://driveteslacanada.ca/news/tesla-fixes-bc-clock-bug-up...
Isn't the same true for all embedded? They seem to have half assing UX in their job description
Isn't it because the nav feature is market specific? People generally don't seem to like nav software brought in from different continents, across the planet.
I got a new samsung smart tv in April and never connected it to the internet. Just noticed (likely because if the DST change) that the date and time was all wrong when it turns on. Could not unnotice it. I was very pleasantly surprised I could manually set it and no internet was required. I expected to be annoyed at it forever or to go down a rabbit hole like this and fail.
https://web.archive.org/web/20261102163049/https://blog.nns....
The revolution against shitty locked down software has begun and I LOVE IT
A blog post and the commiseration of HN randos does not a revolution make.
Has it? Feels like we're just getting more of it all the time.
"Hold on babe, the christmas lights have to finish installing a firmware update", is a real sentence that actual people are saying in 2026.
I was just wondering the same thing for a 2013 Honda Civic - has the screen's (the "head unit"?) firmware been fully dumped and reverse engineered?
How realistic would it be to run fully custom firmware there, and even communicate over usb - for example, if I had a pi running in the car, and it used the usb connection to show things on the built-in display?
I'd love to pwn the head unit in my 2014 Honda CR-V just so I can stop it from sending a "Play" command every time a phone associates with the Bluetooth and the audio system was left "on".
I also have a 2014 CR-V and I hate this too. But even moreso, I hate that there isn't a play/pause button at all. If I need to stop audio (e.g. pulling up to a drivethru, or starting a conversation), I gotta hit the phone. Heaven forbid I'm playing a CD, nothing I can do at that point.
Putting up a bug bounty of "ordering you a pizza" if anyone tackles this!
Had a Chevy that was extremely obnoxious about this. If it was playing over USB it absolutely would not allow it to stop. Hitting pause on the phone would have the car immediately hit play to restart it.
I get pause (for Bluetooth playback, at least) by pushing the volume encoder knob. That works well for me.
It's probably easier to just buy an aftermarket head unit. The only thing you'll need to confirm is that it supports features you care about e.g. steering wheel controls.
Probably more difficult than hijacking the display with the pi. But that's just a vibe.
Okay, this was gratifying to read, but ... can't you wedge CarPlay onto this thing? I'd want a victory lap with root doing at least something. Bad apple on car boot, there's lots of options here!
Yeah, I'll keep working on this to get it to do more stuff that's at least a little bit more useful, if not just a better UI that isn't 90% a useless "No maps found" screen. It's more complicated than it might initially seem because they actually have a kernel module blocking me from mounting non-signed partitions as exec, so I'll need to work around that.
I'll probably post a follow up if I get anywhere with this!
Pretty awesome write up to explain their journey in it all.
I suspect a bunch of car head units will face new problems in the spring when many Canadian provinces will no longer change their clocks. The units won't get updated DST rules.
Happened to my Mazda the other day. Thankfully it supports just setting the timezone and dst flag manually.
which is mind boggling.
my skoda simply has an entry in the menu: DST? which puts the clock one hour ahead or behind.
This posts remind me that when i will be in the market for a new van i will have to decide to get the trafic or the vivaro, solely on the head unit they use (renault ones have had incredibly stupid design decisions for years, on ergonomics alone, even more in firmware)
Yep, in my mind this is one of the hallmarks of a well-designed digital desk clock: a 2-position hardware switch for DST on/off.
Well. In most places. https://en.wikipedia.org/wiki/Daylight_saving_time#Procedure
(edit to be clear: not all places use 1 hour offsets)
I lived for several years in a place that did not observe DST. At least that portion of living there was pretty nice.
That's this fall - happened a couple of days ago.
I wonder how many systems have a good web browser embedded. Last time it was tried on a tesla, it could barely render a maplibre map.
The Web is a universal platform very capable in 2026.
not quite as difficult, but reminds me of a fix I found on reddit for Subaru Outback parasitic drain: https://www.reddit.com/r/subaru/comments/1evozzf/dead_batter...
Usually you can just get a modern OBDII scanner and set it via the diagnostics or hot functions.
Love it! Slightly more elegant than my solution: a piece of electrical tape over the clock.
The Renault Latitude is actually Samsung car right?
I wish someone would jailbreak the Nissan Leaf (MY2018) head unit. Every time I turn on the car, it shows a EULA asking if Nissan can please collect every detail of my car at all times and sell it to whoever asks.
Every. Time.
Even if I beat my head with hammers to think like a lawyer, I can't imagine how it would be necessary to ask constantly. Doesn't matter if I accept or decline, it still asks again.
I hate to laugh but the thought of you constantly rejecting the EULA for weeks on end, to finally give in one day, press accept and come to terms with it, only to get in the next time and have it pop up.
I can only imagine the amount of expletives that were said at that exact moment.
God, I hate modern cars.
Nice! Reminds me of my jailbreaking my car's computer to write a string to permanent memory
https://www.josephecombs.com/2026/09/08/coding-an-audi-batte...
an SD card requirement is crazy
The French auto industry... has always been "Special"
Shitboxing ftw
Meanwhile me with shitbox
8 inches or more of dashboard real estate to display "maps not found", "don't get distracted" warning, terms and conditions, and blinking "12:00". Having had rented a fair share of subcompact and compact cars in half dozen of countries, the car navigation was updated and working exactly only once.
> The system had DRM checks which rejected SD cards without the correct CID (a unique ID burned into the card) and files with signatures based on that specific CID, so I couldn't even copy the files to a blank SD card.
FWIW, there are grey market sites that will sell you an SD burned with a custom CID so you can clone an SD card with this kind of copy protection. It sounds like in this case maybe he could've gotten away with an empty maps card + menu definitions file.
There is code execution exploit in Samsung SD/eMMC firmware which, among other things, will allow changing the CID