Back in 2023, Neowin reported on TPM attestation failures on AMD Ryzen PCs that had been known since December 2022 but were still around at the time, even several months later. We came to know of the bug after some of our forum members alerted us.
On the issue notes, Microsoft wrote, "TPM attestation for AMD platforms with ASP firmware TPM might fail with error code 0x80070490 on Windows systems. This issue is resolved on later versions of AMD firmware. Consult with device manufacturers and firmware release notes for which firmware versions contain the update."
So while Microsoft stated that a future (post-2022) AMD firmware had supposedly already resolved the issue, we were a bit surprised to see that the issue still persisted, and as such, mostly blamed AMD for the problem.
However, it turns out we were not quite right in doing so. While browsing, Neowin spotted a new support article today regarding the TPM attestation failure that is still probably happening, AMD has clarified that the company had released the firmware patch already in 2022 but some of the motherboard vendors did not release that update for users.
The issue affects Ryzen 1000 (Zen1) up to Ryzen 5000 (Zen 3) processors, so it mainly affects AM4 motherboards. AMD further clarifies that "motherboards with AMD fTPM 3.*.0" are affected. If you are not sure the company says:
Run “
Powershell.exe -Command Get-TPM” to determine if the system is impacted by this issue.
The company has explained the situation and its implications and how it can lead systems into BitLocker recovery:
AMD resolved this issue in TPM firmware updates provided to motherboard manufacturers in 2022.
- Some motherboard manufacturers chose not to redistribute these TPM firmware updates.
- BitLocker™ users can suspend BitLocker™ during these TPM firmware updates, which may clear the TPM outside the Windows® API. If users do not suspend BitLocker™, the computer may enter recovery mode when restarting and may require a recovery key or password to access the computer.
We are not sure why the board makers chose not to do so, perhaps they noticed some major issue elsewhere; and so AMD now recommends contacting your board's manufacturer directly if you are still having TPM attestation failures and related BitLocker issues or encountering other problems. For example, AMD notes that gamers may be unable to compete in online cash tournaments.
The company writes:
Contact your motherboard manufacturer’s customer service department to determine if a firmware update is available.
BitLocker lockout can be a massive problem if you are not careful and so it is recommended that you bookmark this official guide from Microsoft. You can find the support article regarding TPM attestation here on AMD's official website.