X370 Taichi and 5900X, major problem.

Howdy folks! I'm stalled here, so any help will be much appreciated!

System specs:

AsRock X370TaiChi
Ryzen X1700 (trying to upgrade to 5900X)
4x 8GB Corsair Vengeance 3200 (worked at 3066 for years)
GTX1070
Samsung 960Evo 500GB NVMe

Finally upgraded to 5900X, or so I thought.

Board worked flawless for more than 5 years with the 1700X, I stayed with BIOS version 2.40 as I was afraid newer versions might break something.

In preparation for the CPU swap I upgraded the BIOS to 7.10 using the bridge versions in-between. Starting with 7.00 I got a warning about bitlocker/ftpm and boot drive becoming inaccessible, but I'm not using bitlocker and I don't know what ftpm does, and frankly not being able to use the same Windows installation after a BIOS or CPU upgrade seems... inappropriate.

Anyway, after upgrading to 7.10 I let the system boot into Windows, all was still ok. However, after swapping the CPU I got this message:

New CPU installed, fTPM/PSP NV corrupted or structure changed.
Press Y to reset fTPM
Press N to keep previous fTPM record and continue system boot.

Pressed N but nothing happened. Waited a few minutes and pressed reset.
Same message appeared so i pressed Y this time. Board restarted a few times then got stuck in a comatose state where:
- it doesn't respond to reset button
- it doesn't respond to power button (short, long, extra-long press, no matter)
- all fans spin at full blast
- it shows no code on the POST display

I must mention that I left it like that for around 10 minutes before trying to reset or power down.

Found some info that using only one stick of RAM increases your chances of success, so I removed 3 out of 4 8GB sticks that I'm using, and at some point Windows said it tried to start but couldn't, tried a repair but during repair the system would reboot and be stuck again in the state described above.

Reset the CMOS, re-flashed the 7.10 BIOS, no avail. Some restarts, codes flasing on the display, then stuck in coma.

Put back the 1700X, Windows started undoing the changes and luckily it seems nothing is lost. I made a backup of critical stuff before starting the BIOS updates, but I'd very much like to keep the current Windows install.

At this point I'm out of ideas, I don't know if the systems gets stuck that way because it doesn't like my Windows install, or the board is not really compatible with 5000-series. Wouldn't surprise me too much, as my previous board (AsRock 880G Extreme-3) claimed to be AM3+ compatible with the latest BIOS, but I encountered much strangeness when trying a FX cpu so had to send it back and revert to my Phenom.

Thank you very much!

You put me on the right path, I read a bit about TPM then proceeded to:

- "Clear TPM" via tpm.msc from Windows, with old processor installed
- disable TPM in UEFI, save settings. Windows still booting fine.
- shutdown to install new CPU, Windows boots from first attempt
- shutdown again to install all the RAM, and I even have all 4 sticks working at 3200MHz which was impossible in 5 and a half years.

Thanks again, you've made my day!

Nah, I spoke too soon, it seems more frustration is in store for me.

I enjoyed the new CPU for a couple of hours, everything stable and quick as it should be, did some benchmarking, monitored things, I was glad that it was boosting to 4.95GHz.

Then I wanted to shut down to fit both fans to the Noctua cooler and tidy things that were un-tidied during my attempts.

But instead of powering down, the system entered the dreadful state where I had to switch the PSU off! And then again it wouldn't boot, as described in first post. At one of the attempts the message was "Starting automatic repair" or something like that, but after some seconds it locked again!

I'll do a fresh install on a spare SSD and see how things go...