I’ve built a box for the xoxbox. I killed the decay circuit somewhere along the way doing this.
A couple of build notes for posterity here. The fuse settings:
XOX avr default fuses are: 62 99 ff new values: FF D4 F9 avrdude -c usbtiny -p atmega162 -U lfuse:w:<0xFF>:m avrdude -c usbtiny -p atmega162 -U hfuse:w:<0xD4>:m avrdude -c usbtiny -p atmega162 -U efuse:w:<0xF9>:m
Also the eeprom that we used needs to have the write protect bits turned off, this was not the case for the original.