You are right. The CPU is the IAP15F2K61S, which is in principle a 80C51 processor, so totally different than the AVR.
I have also send a mail to trusfer to see if they can sell me a different board for gcode.
They have it in their program, so I think it must be possible.
Otherwise I will mount a standard EleksMaker board.
I would like tu use this small machine for cutting and mot for engraving.