December Adventure 3rd 2025

3rd Dec

Project

Finally had a bit a time to get to work on building this test rig. The Samsung A5 I got off ebay is a bit of a disaster, the back plate is pretty much destroyed, the battery is swollen and its missing 2 buttons. I’ve been working with this model for a number of weeks and I’ve learnt that they are super robust, I therefore removed the back case (which was easy as it is shattered) then took off the screwed down cover, removed the battery and replaced it with one from another device.

Luckily it booted up but was locked to the previous user, I therefore rebooted and went into Android Recovery System (pressing the on button, the home button and volume up - 2 of these are missing so I had to poke tweezers into the holes to activate them). I wiped the system partition and cache and then let it boot back up into the setup system. As this device has been used before it was locked to an unknown google account so I used the software Droidkit to bypass the google lock. This allows you to boot into a fresh android installation and due to the bypass actually puts you into developer mode, this revealed an issue, they hardware was detecting moisture in the usb-c port, there wasn’t any moisture but it looks pretty busted up so probably is triggering - luckily as I don’t have plans to use android this isn’t a big issue.

Next step was to boot into Odin recovery (power, home and volume down buttons at boot) and then using Heimdall was able to flash TWRP into the recovery partition, I then had to be quick and hold down power home and volume up to boot into TWRP before it got overwritten. Due to the lack of buttons it required a complicated arrangement of my hands to ensure everything was pressed at the right time. Once in TWRP I could then sideload via adb an image of postmarketOS, it took a few trys due to the poor state of the usb-c port but eventually managed to get it to flash, a reboot and we were happily booting into linux!

I’m a little suprised that this busted up smartphone was able to be rescused but they are well built, interestingly it seems that they have developed a hardware trigger to a swollen battery, when the battery swells it will lift the back plate off which disconnects the power button contacts, I assume this is a safety mechanism. The good news is that most ‘dead’ Samsung A5’s aren’t actually dead, just need a new battery.

Tomorrows task will be trying to solder 2 wires to bring out the serial port, I’ve had a lot of practice but the pads are so small and next to each other there is very little margin for error, I’ve got some new flux which hopefully will help (I suspect my old flux was well past its best before date) and have very tiny enamelled wire.

Reading

Managed to squeeze in some reading in the evening, just a short story from the Futures To Live By collection called “Anatomy of Emotion – the Carving of Chance – Seize the Moon”, it was an interesting take on a seasonal community in a post-collapse landscape who live happily in the shadow of a fallen (and reclaimed by the wild city). I enjoyed the fact that it really focused on human relationships to guide the story and the solarpunk/world building was more in the background.