Hey guys,
As suggested in the title, how to i use -F to override the signatures.
I've tried changing it to 0x14 and it didnt work =(
avrdude: Yikes! Invalid device signature.
Double check connections and try again, or use -F to override
this check.
Error while burning bootloader.
Normally, you do not actually want to use -F when you get this message, and it wouldn't help if you did use it.
The "invalid signature" message usually indicates a wiring error of some kind (except for cases where you see an ATmega328 signature and want it to look like an ATmega328p, which you can tell with "verbose" mode.)
Enable Verbose Upload in settings, reattempt that process. That will tell you what it's actually reading. If it's 0x000000 or 0xFFFFFF there's a wiring problem or the chip is expecting a crystal and none is present. Incrementing numbers (ie, 0x000102 ) suggests that reset is shorted to ground.
The only time it would ever make sense to use -F is if you're programming a chip with corrupted signature bytes - otherwise, if the signature check didn't work, neither will any other programming operation.