In addition to the EEPROM, the ATtiny1617/3217 has one extra page of EEPROM memory that can be used for firmware settings, the User Row (USERROW). This memory supports single byte read and write as the normal EEPROM. The CPU can write and read this memory as normal EEPROM and the UPDI can write and read it as a normal EEPROM memory if the part is unlocked. The User Row can be written by the UPDI when the part is locked. USERROW is not affected by a chip erase.