[drited]

Is this why people elsewhere in this thread are saying that a bios update can brick a machine which uses bitlocker? I guess if a user doesn't have the key saved, a bios update would result in a request for the decryption key that can't be satisfied?

[bri3d]

Right, a BIOS upgrade will break the hash chain, because the system has gone and replaced the current trusted early boot software with new early boot software.