Jan, I apologize in advance as I am not at all good in GIT so no pull request.
I have modified the bootloader and also the lib-example to fully support the five button version (with a middle button) as also depicted in Ben's official schematics on his website.
Buttons assigned as follows:
PA0 Middle
PA1 Up
PA2 Down
PA3 Left
PA4 Right
Modification was quite easy. Just remove the ROR , additionally evaluate $10 and reaarrange all menu controlls to th new key mapping.
I attach both asm-files. Maybe, you can update!
Cheers
Armin
5button_bootloader_Using_rom_lib_asm.zip