ref: 21ae833386940c7414ecaaf1012c0ec87f0088e5
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