Xprog error: Unknown command. Software error
Solution: exchange your Xprog CPU with a new chip
Tools you need:
A working Xprog-m programmer
A high-quality Atmega64 repair chip
Note: you need different Atmega64 repair chips for different xprog versions you wanna update to.
The chip for the newest Xprog v5.70 and v5.60 is not available now.
It can be got with Xprog programmers only!
Xprog v5.70 here: