iBootLoader: Arduino Custom Bootloader with Rollback Feature

This repository contains a custom bootloader for Arduino that adds a rollback feature for firmware updates using an external I2C EEPROM memory IC (24LC512). This bootloader ensures that if a new firmware update fails, the Arduino device can automatically revert to the previous working firmware.

Features

• Firmware Rollback: Automatically revert to the previous firmware if the new firmware fails to execute properly.
• I2C EEPROM (24LC512) Integration: Stores two firmware slots, configuration data, and reserved space in the external EEPROM.
• Watchdog Timer (WDT) Support: Utilizes WDT to monitor the success of the new firmware execution and trigger a rollback if necessary.
• Configurable via I2C: Firmware and configuration data can be managed via the I2C bus.

Memory Layout

The 64KB EEPROM (24LC512) is divided into the following sections:

• Firmware Slot 1: 30KB - Stores the new firmware during the update process.
• Firmware Slot 2: 30KB - Stores the previous working firmware as a backup.
• Config Space: 2KB - Holds configuration settings for the bootloader and firmware update process.
• Reserved Space: 2KB - Reserved for future use or additional configuration.

Bootloader Workflow

1. Firmware Upload:

   • A script named manage_fwu_eeprom.py is used to upload the new firmware to Firmware Slot 1 in the EEPROM and update the configuration space via the I2C bus.
   • After uploading, the Arduino device needs to be reset.

2. Firmware Update Process:

   • On reset, the bootloader reads the configuration space and initiates the firmware update.
   • The current working firmware is copied from the Arduino's memory to Firmware Slot 2 in the EEPROM (backup).
   • The new firmware from Firmware Slot 1 overwrites the working firmware in the Arduino's memory.
   • The configuration space is updated again to reflect the new firmware.

3. Execution and WDT:

   • The bootloader sets the Watchdog Timer (WDT) and jumps to the starting address of the new firmware.
   • The firmware is responsible for turning off the WDT during its initialization.
   • If the firmware fails to turn off the WDT, the WDT will reset the Arduino.

4. Rollback Mechanism:

   • If the WDT reset occurs, the bootloader assumes the new firmware failed.
   • The bootloader will then restore the previous firmware from Firmware Slot 2 in the EEPROM back to the Arduino's memory.
   • The bootloader jumps to the restored firmware to resume normal operation.

Prerequisites

• Arduino board with I2C capability.
• 24LC512 EEPROM (or equivalent) connected via I2C.
• Python environment for running the manage_fwu_eeprom.py script.

Getting Started

1. Connect the 24LC512 EEPROM to your Arduino via the I2C bus.
2. Upload the Bootloader to your Arduino board.
3. Use the manage_fwu_eeprom.py script to send new firmware to the EEPROM and update the configuration.
4. Reset the Arduino to initiate the firmware update process.

Script Details

• manage_fwu_eeprom.py: A Python script for managing firmware updates via I2C. It handles writing the new firmware to the EEPROM and updating the configuration space.

Contributing

Feel free to contribute to this project by opening issues, submitting pull requests, or suggesting new features.

License

This project is licensed under the MIT License.