How can I see if Windows is refusing to trust a TPM?

Asked Aug 22 '18 at 16:44

Active Aug 23 '18 at 03:49

Viewed 121 times

I've been fighting with my motherboard's manufacturer to get a TPM I bought from them to work. In UEFI/BIOS I can see the TPM and set its state to enabled, but in tpm.msc it just reads that no compatible TPM was found (see screenshot), and it does not appear in Windows Device Manager either.

Note that this alert is the exact same if you have the TPM installed or not

After RMA-ing the TPM and having the swapped unit still not work, I'm pretty confident that the issue is with Windows refusing to trust the TPM due to out of date or insecure firmware. The problem is, how can I be sure of this?

I've looked through Windows Event Viewer to try and find some event that shows that Windows sees the TPM, but doesn't accept it, but couldn't find anything.

Is there any way I can test this TPM against Windows and see that it isn't trusted?

edited Aug 23 '18 at 03:49

JonathanDavidArndt

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asked Aug 22 '18 at 16:44

ecnepsnai

What is the output of: `wmic /namespace:\\root\CIMV2\Security\MicrosoftTpm path Win32_Tpm get *` – Greg Askew Aug 22 '18 at 17:26
@GregAskew `No Instance(s) Available`, which is the same output I see on a computer that doesn't have any TPM installed. – ecnepsnai Aug 22 '18 at 17:28
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Doesn't sound like trust, sounds like Windows is not recognizing the hardware or there is a hardware problem. What model server and TPM chip is it, and what TPM spec versions are displayed in the BIOS? – Greg Askew Aug 22 '18 at 20:04
Does the TPM appear in Device Manager? – Harry Johnston Aug 23 '18 at 01:46
@HarryJohnston it does not, as stated in the question. – ecnepsnai Aug 23 '18 at 02:02
@GregAskew It's an Asus TPM-L R2.0. Just an infinion TPM. Other than controlling the state and the action, there's no version information in the BIOS. – ecnepsnai Aug 23 '18 at 02:03
Any unrecognized devices showing up? – Harry Johnston Aug 23 '18 at 02:34
@HarryJohnston No, I'll update the post to include a screenshot of the device manager. – ecnepsnai Aug 23 '18 at 02:34
This may be (another!) silly question, but how is the TPM physically connected? I've only ever seen TPMs that are built into the motherboard. – Harry Johnston Aug 23 '18 at 02:36
@HarryJohnston There's a 20-pin header on the motherboard where it is plugged in. – ecnepsnai Aug 23 '18 at 02:37
Asus TPM-L R2.0 appears to be a TPM 2.0 device. Does your UEFI firmware support TPM 2? What is the output of the `ver` coomand at your UEFI shell prompt? – fpmurphy Aug 23 '18 at 04:33
@fpmurphy1 the revision was 2.4 – ecnepsnai Aug 23 '18 at 04:48
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Version 2.4 should hande TPM 2.0 without an issue so that does not seem to be the problem. If you can build UEFI utillities, have a look at `ShowTPM2` and `ShowTCM20` at https://github.com/fpmurphy/UEFI-Utilities-2016/tree/master/MyApps – fpmurphy Aug 23 '18 at 05:02
Powershell will tell you with `Get-Tpm`. – bjoster Sep 06 '18 at 13:41

How can I see if Windows is refusing to trust a TPM?

0 Answers0