This is done off board with qfp64 breakout board should be able to program onboard xprog also though.
EXTREME BURNER SOFTWARE AND 10 TO 6PIN ADAPTER
you will need to split vcc + into 3 wires and gnd – into 3 wires
atmega should connect as normal
Then tick all the write boxs and click write. or you can manually enter the following
( Low E1, HIGH 99, EXTENDED FD, LOCK FF then click write these are factory lockbits. see photo
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