EEPROM_SUM
if (checksum == (uint16_t) EEPROM_SUM)
checksum = (uint16_t) EEPROM_SUM - checksum;
if(checksum == (uint16_t)EEPROM_SUM)
checksum = (uint16_t)EEPROM_SUM - checksum;
if(checksum != (uint16_t)EEPROM_SUM) {