ref: 0aae832ac3f3ae5d136563e980e9c32ceb0d1444
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