I have several HP desktops running latest Windows 10 and requiring a TPM firmware upgrade (sp82407.exe) to fix last year's faulty Infineon crypto vulnerability. The updater requires the TPM to be initialized, and requires the user to input either the passphrase, or the key backup file to proceed.
Windows 10 refuses to bring up the passphrase entry / key backup dialog during TPM initialization, no matter what I try. All the guides I read are either outdated or outright wrong. On Win7 it used to be easy, the option to manually initialize was right there in tpm.msc. But Win10 at some point changed it, so that by default, for security reasons, a random key is generated and then discarded. So now upgrading the firmware is impossible.
This is made even worse by the TPM's requirement to be physically present to press F3 at boot time to confirm the TPM clearing step. I have spent literally hours on-site repeatedly restarting a slowly-booting PC and trying various commands and toggles from guides I found. It's frustrating and upsetting. Neither Microsoft nor HP acknowledge any of this behavior in their TPM documentation, and the firmware upgrade tool does not accomodate for this new Windows behavior.
So, can anyone provide working instructions for how to switch TPM initialization into manual mode on latest Windows 10?