For posterity's sake (I hate forum threads that don't provide a result at the end), apparently some Hifiwalker H2 V1.3 units have some sort of bug where it is impossible to get into the OF's updater. The device will simply reboot with no change if you select Firmware Update from the original firmware, or will just continuously reboot if you hold VolUp+Power to attempt to go directly into the updater. I will update the wiki to note that this is a possibility.