Some Dell Latitude 5520 models have a BIOS reset jumper that can be used to reset the BIOS password. Here's how to use it:

For authorized users, Dell provides a recovery mechanism based on a and a Master Password generated by their internal algorithm.

If the laptop is enrolled in or Dell Auto Pilot :

Before attempting to reset the BIOS password, make sure to:

For extreme cases where software codes fail (often due to specific enterprise security settings), the only remaining option is to manually flash the BIOS chips using an external programmer. This requires disassembling the laptop and soldering skills, which should only be attempted by professional repair technicians. Are you currently seeing a specific suffix (like -8FC8 or -E7A8) on your locked screen?

Warning: This voids warranties and requires advanced microsoldering skills.