Often, OTPBIN contains high-entropy keys, while EEPROMBIN has structured user data. For testing without hardware:
# Check for entropy (high entropy = encrypted/crypto keys) ent otp.bin strings -n 8 eeprom.bin Analyze with binwalk binwalk otp.bin otpbin seeprombin upd
import struct eeprom_data = bytearray(1024) eeprom_data[0:4] = b'EEPR' eeprom_data[4:6] = struct.pack('<H', 1) # version 1 # Write some settings eeprom_data[64:68] = struct.pack('<I', 115200) # baud rate crc = zlib.crc32(eeprom_data) & 0xFFFF eeprom_data[1022:1024] = struct.pack('<H', crc) with open('eeprom.bin', 'wb') as f: f.write(eeprom_data) To flash an EEPROMBIN to an AVR: OTPBIN contains high-entropy keys