Whenever you buy used computers there is a risk that they come with unpleasant surprises that are not of the insect variant. From Apple hardware that is iCloud-locked with the original owner MIA to PCs that have BIOS passwords, some of these are more severe than others. In the case of BIOS passwords, these tend to be more of an annoyance that’s easily fixed by clearing the CMOS memory, but this isn’t always the case as [Casey Bralla] found with a former student-issued HP ProBook laptop purchased off Facebook Marketplace.

Maybe it’s because HP figured that locking down access to the BIOS is essential on systems that find their way into the hands of bored and enterprising students, but these laptops write the encrypted password and associated settings to a separate Flash memory. Although a master key purportedly exists, HP’s policy here is to replace the system board. Further, while there are some recovery options that do not involve reflashing this Flash memory, they require answers to recovery questions.

This led [Casey] to try brute-force cracking, starting with a Rust-based project on GitHub that promised much but failed to even build. Undeterred, he tasked the Claude AI to write a Python script to do the brute-forcing via the Windows-based HP BIOS utility. The chatbot was also asked to generate multiple lists of unique passwords to try that might be candidates based on some human guesses.

Six months later of near-continuous attempts at nine seconds per try, this method failed to produce a hit, but at least the laptop can still be used, just without BIOS access. This may require [Casey] to work up the courage to do some hardware hacking and erase that pesky UEFI BIOS administrator password, proving at least that apparently it’s fairly good BIOS security.