http://c25o7knygjm3m67jy27yuynvv4pkfi25naucscmh4ubq2ggiig3v57ad.onion/en/guix-on-an-arm-board.html
Most boards
use the u-boot bootloader, so we will focus on that bootloader here. Contrary to grub, there are multiple variants of u-boot, one per board type. The installation
procedure for u-boot is also somewhat specific to the board, so there are two things that you
need to take care of: the u-boot package and the bootloader declaration.