Could this not be made possible within UCCNC in "Offline" mode, by uccnc storing the XYZABC co-ordinates + any G5x offsets into memory and then resetting them when disabling Offline mode
Given the machine has not moved restoring these positions should set everything back to homed positions?
{would also need to cancel any macros that may have not been terminated - is it not possible to create a "soft" E-stop {one that does not toggle the physical outputs of the motion controller, that way all macros will be terminated??}
Just thinking aloud