Lenovo EC related firmware mods (oem batt, xx20 keyboard, alt-ctrl keyswap)

[tlaurion]

New OEM batteries are not really available and they need to patch the EC for the replacement battery they got.
Also there are issues if you have not updated the lenovo bios ever before and the outdated EC from the first lenovo bios releases is known to make problems with coreboot.
The most common way to make a thinkpad ready for flashing coreboot is this project here: https://github.com/hamishcoleman/thinkpad-ec
If you missed this step before flashing coreboot, in general you are stuck at reflashing the lenovo OEM bios file and then lock your SPI again. And then you have again to open up your device once again and redo everything or you have to learn how to remove the write protection in the OEM Lenovo image before writing it to the SPI and this is really terrible documented.

To be able to flash inside heads the EC of the Thinkpad would be some great improvement. If you for example decide ever later to use a x20 keyboard in a x30 Thinkpad you can just change the EC with heads.

Originally posted by @fhvyhjriur in linuxboot/heads#1639 (comment)