The ESP's homed flag survives bbctrl restarts (since the ESP itself
stays powered). Host state, on the other hand, gets reset to zero on
boot - State.reset zeros ap and offset_a. Trusting the ESP's homed
flag in that situation made gplan think A was homed at machine-coord 0
while physically the axis was at 134, which then rejected any move
to the bottom (G1 A-134) as 'less than minimum soft limit 0'.
Send UNHOME (new auxcnc verb that just clears g_homed without
moving) on every host connect. The user has to re-home explicitly,
which goes through the proper Mach.home path that sets up the
offset and gplan position consistently.
Falls back to HOMED? if the firmware doesn't know UNHOME, so older
auxcnc builds keep their previous behaviour.
State.reset extended to also clear motor 4's homed flags
(<motor>homed and <motor>h) so the synthetic external-axis motor
gets reset alongside the real AVR motors.
Henrik Muehe
53b65dc30e