ref: dc952dad295700a836cf91ec66b1c443e5bbb4b7
dir: /sys/src/boot/reform/boot.txt/
mw.b 0x40010000 0x0 0x10000 load ${devtype} ${devnum}:${bootpart} 0x40010000 ${prefix}plan9.ini load ${devtype} ${devnum}:${bootpart} 0x40100000 ${prefix}9reform.u bootm 0x40100000