Re: [avr-chat] How can I individualise specific CPUs?

[Juergen Harms]

I did not see the real problem: the "chip erase" required before 
programming resets the lock bits. That means that downloading (parallel 
or serial programming actions) will practically always also erase the 
bootloader (unless the EESAVE fuse bit is programmed, but so far I 
looked for a solution that allows to download into flash and eeprom).

Atmel evidently expects that either the bootloader is used more or less 
exclusively, or the programming mechanism - but not the kind of 
combination I had considered.

Too bad. An alternative would be to use the calibration eeprom byte (I 
use an external crystal) - but that is a kind of approach which 
interferes with settings that are probably better left as they are 
shipped with the part.