avrciczz.asm - source code avrciczz.elf - binary + fuse bits settings avrciczz.hex - binary only. SUT_CKSEL fuse should be set to "ext clock + 0ms" in case if avrciczz.hex was used, avrciczz.elf already contains this setting Push the reset 4-8 times after than system region was changed, or if cic used at first time chip pinout inside of avrciczz.asm file