This article provides a comprehensive guide to understanding (One-Time Programmable Binary), EEPROMBIN (Electrically Erasable Programmable Read-Only Memory Binary), and UPD (Update/Upgrade Procedure). By the end, you'll understand how to generate, flash, verify, and troubleshoot these binary images across popular platforms like AVR, STM32, ESP32, and 8051-based chips. Part 1: What is OTPBIN? 1.1 Defining One-Time Programmable (OTP) Memory OTP memory is a type of non-volatile storage that can be written exactly once. After a bit is flipped from its default state (usually 1 to 0 ), it cannot be changed back. This is physically enforced by blowing polysilicon fuses or antifuses inside the chip.
avrdude -c usbasp -p m328p -U eeprom:r:backup_eeprom.bin:r For Espressif chips (ESP8266/ESP32) using esptool.py :
avrdude -c usbasp -p m328p -U otp:w:otp.bin:r On STM32 using stm32flash : otpbin seeprombin upd
stm32flash -w otp.bin -v -o 0x1FFF7800 /dev/ttyUSB0 Mistakenly writing OTPBIN with wrong data can brick the device’s security features. Always verify the binary before flashing. Part 2: Decoding EEPROMBIN 2.1 What is EEPROMBIN? EEPROMBIN is a binary image of EEPROM data—memory that is byte-addressable, can be erased and rewritten many times (typically 100k to 1M cycles), and retains data without power. Unlike OTP, EEPROM is flexible but slower and larger.
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: This article provides a comprehensive guide to understanding
[HEADER: 4 bytes MAGIC "EEPR"] [VERSION: 2 bytes] [DATA...] [CRC16: 2 bytes] Example creation script:
| Offset | Size | Content | Purpose | |--------|------|------------------------|----------------------------------| | 0x00 | 8 | Unique ID | Factory serial | | 0x08 | 16 | AES-128 key | Secure boot | | 0x18 | 4 | Lock bits | Disable debug interface | | 0x1C | 4 | CRC32 | Integrity check | Using standard Linux tools or MCU vendor tools: avrdude -c usbasp -p m328p -U eeprom:r:backup_eeprom
Introduction In the world of embedded systems, few things are as critical—or as misunderstood—as the management of non-volatile memory. For firmware engineers, reverse engineers, and hardware security researchers, three terms frequently appear in datasheets, programmer logs, and debug outputs: OTPBIN , EEPROMBIN , and UPD . While they may look like random concatenations, they represent distinct concepts in microcontroller (MCU) programming.