I'm using an Atmega16u4, so that I can later update field units via USB DFU. I'm able to connect and upload my firmware via FLIP, but I need to also change a couple fuses (CLKDIV8, for one). From what I've read, I need to connect via ISP and perform a full chip erase to be able to change fuses. (I get a "One or more registers does not match" failure.) Can anyone confirm this?
And if I do a full chip erase, I'm pretty darn sure I erase the bootloader too. Ah jeez.
Do I need another step in there? Like load in the LUFA bootloader before loading in my production firmware? Would that work, as long as I don't do another chip erase before final programming? (I'm not sure how overwriting/ protection of LUFA works.) Like so:
- Full chip erase via ISP
- Load LUFA bootloader via ISP
- Load production flash/ fuse .elf via ISP
- Future updates possible in field via USB
Any help is greatly appreciated,