Win10-Win8.1 TPM Reset

From Wiki.CoreyBlair.US
Jump to navigation Jump to search

I noticed this bug while working on surface 3s at work. The issue is that windows 10 is encrypted from the start with blank keys so that when you decide to apply the keys, the drive doesn't have to do anything further. Think of it as a gate that is closed with a hanging lock on it. The issue is that the TPM is expecting keys from Windows 10 and thinks something screwy is going on when you try to initialize it with Windows 8.1.

You will be prompted with a message that says the following, "The TPM is defending against dictionary attacks and is in a time-out period."

The solution is to issue some Powershell commands after running it as administrator. Also note that a restart is required after the commands have been issued, at which time you will be prompted with a black screen asking you if you are sure you want to fully reset the TPM. These commands are as follows and should be issued individually.

$tpm=get-wmiobject -class Win32_Tpm -namespace root\cimv2\security\microsofttpm

$tpm.DisableAutoProvisioning()

$tpm.SetPhysicalPresenceRequest(22)

The original information can be found HERE.