If you can already access your BIOS but want more tuning options (like XMP or undervolting), you can often use a "secret" key combination . Lenovo ThinkPad T480 - Administrator BIOS Unlock
If you are the original owner of the device, there are safer paths to regaining access:
Firmware may be set to only allow booting from the internal drive, preventing the installation of new operating systems. 2. Official Lenovo Management Tools
If you can already access your BIOS but want more tuning options (like XMP or undervolting), you can often use a "secret" key combination . Lenovo ThinkPad T480 - Administrator BIOS Unlock
If you are the original owner of the device, there are safer paths to regaining access:
Firmware may be set to only allow booting from the internal drive, preventing the installation of new operating systems. 2. Official Lenovo Management Tools