I've got a question regarding the internal EEPROM of an ATmega328(P). Sadly the datasheet has no information for me.
Question: What happens if I use the Write-Only Mode on non-erased (!= 0xff) EEPROM cells (EEPM1 = 1)?
I tried simulating this special case in a simulator (not Atmel Studio). The simulator writes (independently from the contents of EEDR) 0x00 if I try writing in write-only mode to a non-erased cell.