Hello everyone! I made a patch to the EC firmware that turns off the fans when temperatures are low. This took me almost a week! The patch is for European EC firmware!
Note that the temperatures are very bad on my machine, probably because I disassembled it, so the fans keep turning on. But they turn off eventually so at least some battery is saved! Anyway, you can roll back it at any time if you’ll experience the same.
I’M NOT RESPONSIBLE FOR YOUR BRICKED LAPTOPS! DO THIS AT YOUR OWN RISK!
Our EC is IT8987 which contains the 8051 CPU inside. Official docs for this EC are not available, however you can find datasheets for similar chips, for example IT8570E or IT8511E. You can find the common part of EC firmware on GitHub, but you have to RE the OEM part. 8051 controller is 8-bit, but it’s very easy to learn how it works because of it’s simplicity :). Note that the firmware is divided into 4 “memory banks” (1 common at address 0, 3 other switchable, starting at 0x8000, bank size is 0x8000 bytes each), but the last one is not used. So 2+1 banks in total. The part that controls the fans is in 2nd bank. The patch is literally 1-byte.
Happy new year!