I resolved my issue by updating the ME first. Install this in Windows first before updating the BIOS: https://rog.asus.com/forum/showthread.php?117768-FIRMWARE-Intel-ME-(H470-Z490)
I solved the problem without buying anything.
1. Flashback to 2201.
2. Update to 9902 bios (the CAP file) using Asus EZ Flash (bios tools) from this thread on Reddit https://www.reddit.com/r/ASUS/comments/o9x8r0/ptt_issues/
(it was shared by taviso who got it from the Asus support, it seems to be some developer version and it upgrades/downgrades ME firmware to the version that is compatible with the new versions of bios).
3. Enable PTT, save and reset, check that PTT is still enabled.
4. Flash 2301 with EZ Flash, it reboots couple of times, check that it is working.
5. Flash 2701.
Thanks mishurov. Also fixed the problem for me. I updated Intel ME based on the BIOS notes on the Asus site and this then stopped me booting. Had to downgrade to 2201 to at least boot Windows. Asus support wanted me to RMA.
9902 seemed to be the fix though. It had a screen about updating Intel ME. The version number reported before and after the BIOS update for Intel ME is the same though - 126.96.36.1999V1
It's on the Z490-E support page. I wouldn't install it though unless you’re feeling like you potentially want to RMA your board.
The 9902 firmware might be the fix as that got it working for me but it doesn’t really seem to be something offered up by Asus as a solution to everybody.
Thanks for the swift reply.
I was about to update with Mokichu's latest ME Firmware : 188.8.131.528 [13/02/2023] and then install the 2701 BIOS
But, having suffered for two years (unable to get the latest bios to run Win11), I think I will lurk and watch for now.
It might be fine. To be honest my z490-I had been doing this weird thing after installing any BIOS >2201 where on cold boot it would turn on, turn off and back on again. I just assumed it was Asus doing something weird to get the Win 11 support on the board. Whatever the 9902 BIOS did it resolved the boot problem and now on the latest BIOS it no longer behaves like that on cold boot, it just boots normally.
I do wonder now if I could update Intel ME but reluctant to push it given everything seems to be working fine for the moment.
Updating to the latest ME firmware (from Mokichu) sometime in 2021 was how it started for me. I updated to the then latest ME firmware from Mokichu and then tried to install the lastest BIOS. I could not get past the boot-loop problem you described on any BIOS other than 2201.
I tied so many combinations of things over 2 years to fix it. I only got around it by simply buying a new unit of the Z490-I for cheap with the 0607 BIOS. Went straight to the 2601 BIOS from there (I think the BIOS update to 2601 also installed the ME firmware 184.108.40.2068). I did not know about the 9902 firmware at that point. I had never come across that reddit thread.
I am going to guess that since you already have the BIOS 2701 up and running, updating the ME firmware with Mokichu's should be fine! Good luck if you trying it. As for me, I am going to stay put with what I have for now.