HP Z640 CMT TPM not seen by Windows and greyed out in BIOS after updating TPM to 2.0

[JWW-CSISD]

Note: hyperlinks point to the Wayback Machine at archive.org in case of future website redesign by HP.

I wanted to upgrade the TPM in my HPZ640 CMT to 2.0 for multiple reasons: Hyper-V compatibility and possible upgrade to Windows 11.

My computer is running BIOS M60 v02.61 Rev A dated 03/23/2023.

I managed to find HP Customer Support Knowledge Base Document ID c05792935 from which I downloaded and used sp87753.exe to update my TPM to 2.0. Everything appeared to go fine, until I rebooted to complete the update.

After the update, tpm.msc says "Compatible TPM cannot be found", and I have no device category for "Security devices" listed in Device Manager unless I select "Show Hidden Devices"... at which point, it shows Trusted Platform Module 1.2 greyed out:

DeviceManager-TPM1.2GreyedOut

So I went to check in BIOS under Security > TPM Embedded Security, and I discovered it now shows TPM Specification Version 2.0, but all of the drop-down menus are greyed out:

BIOS-TPM-Screen

After doing some digging, I found several references saying that both HP and some other manufacturers require a BIOS Admin Password to be set before it will allow TPM to be enabled/modified, so I set an Admin password and rebooted, but there was no change: the TPM BIOS screen was still greyed out, and there was still no TPM detected by Windows 10.

I tried running sysprep /generalize /oobe in the hopes that the OOBE pass could detect and install the TPM. No luck.

Out of desperation, I even tried a format/reinstall of Windows 10 22H2 from USB/ISO. Even after running Windows Updates and installing all driver updates... still no TPM.

Anyone have any other suggestions?

[DGroves]

reset the bios to "FACTORY DEFAULTS" by removing the power cord then the side cover and press the cmos reset button for 10 sec (or remove cmos batt for 10 sec then reinstall)

now power on, if the reset was successful you will be prompted to set time/date

now under the bios security tab Find a listing for TPM, make sure it's enabled

for readers the z640  update to v2.0 TPM is 

https://ftp.hp.com/pub/softpaq/sp87501-88000/sp87753.exe

https://support.hp.com/us-en/document/c05792935

Start an elevated Powershell window and type: TPM.msc it will show the current ver and status of TPM

[JWW-CSISD]

Well, this was helpful in getting my TPM reset back to 1.2 and reactivated, however, it still won't upgrade either from 1.2 v.40.119.0 to 1.2 v4.43.257.0 or to 2.0 v5.62.3126.0, despite both the GUI and the TPMConfig64.log files indicating a successful upgrade.