i've been trying to find out, mostly out of curiosity, which and what for, are the portions of flash that a user can read&write and which are factory locked/burned.
I'm talking about the mega328, but any mega/tiny chip for that matter.
So far i managed to find:
User accessible: app flash, I/O registers, general purpose registers
Factory preset: device signatures, ... ???
Is anybody knowledgeable about, which flash parts are factory preset and immutable and possibly what are they used for?