When learning a new programming language, it’s best to have a goal in mind and work towards it. [Timo] thought it was about time to learn python, and he also had a project in mind: removing the BIOS supervisor password from his old Thinkpad. From there it was just a few keystrokes (and some soldering) and he was able to change the BIOS password of this black box from the outside.
The build utilizes a BeagleBone to communicate with the laptop’s EEPROM via the I2C bus. An oscilloscope also monitors the bus to look for a specific window every four-seconds when the computer is not accessing the bus. During that short period, the EEPROM can be read and written to. Once the window opens, the BeagleBone executes the Python script, which attempts to read the EEPROM and can also perform actions such as removing or changing the BIOS supervisor password.
Of course, tinkering with the EEPROM on a laptop has a high risk of bricking the device, and not all laptops use the same security measures or even memory addresses for things like this, so documentation and precision are key. Also, with Thinkpads of this vintage it’s possible to replace the firmware on these chips entirely with a FOSS version called libreboot, and even though the process is difficult, it’s definitely recommended.
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