I did a write up on changing the bootloader for more available EEPROM space on a Nano.
/g/BITX20/message/85002using the Arduino as an ISP.
The ArdunioISP code is directly from the sketchbook examples and there is documentation in that sketch.
some documentation in my write up, and a bunch of pictorial write-ups on line.
When I originally used a genuine Uno R3 as the programmer I didn't need a capacitor on RST.
The Nano (clone) I have set-up currently does require that cap.?
With AVRdude and the ArduinoISP, you can dump and load EEPROM, Flash and fuse.? So you can back-up and restore.
I gave some examples, just not examples for everything.? i.e. example on how to dump flash but not load it.
... figured a person could read AVRdude documentation.
Be very cautious on changing fuse settings.? You can brick the Nano where it can't be restored via ICSP.
(it can be restored, but you need a parallel programmer)
You don't need to change the fuses when just dumping or loading EEPROM or flash.
Using the programmer to dump EEPROM may not be the easiest path, but a generic path none the less.
Rgds,
Gary
