Disregard my former post, pls. I had an “Aha!” moment and realized I was asking the wrong questions wrt GPT vs NTFS.
I edited the original post with my new information. Apologies to anyone who read this earlier.
I have this same issue with a Ryzen 5 5600, Gigabyte B450 Aorus Pro Wifi system. I am doing this update for a friend, and things started at the Rev 1.x BIOS level (F1). I started by “walking” the BIOS up going through several interim updates to get to F63, which looks like the minimum that will support Win11.
The TPM is now enabled, but I can’t get the secure boot part done. This is a machine someone else built 4 years ago and now asked me to upgrade (was a Ryzen 2400G CPU) and do the Win11 update. When it was built, the C: drive (2.5 SSD) was set up as an MBR disk, and formatted to NTFS and for some reason it has four partitions. So, mbr2gpt won’t work and neither will the tools available online as all seem to require 3 partitions or less to do the conversion.
My solution is to clone the Win10 install onto the larger drive and then use the cloned drive as the boot drive. I should be able to then set the BIOS secure boot option to be available. We will see.
Gigabyte B450 Aorus Pro WiFi (F63 BIOS)
Ryzen 5600
16 GB RAM (2×8)
AMD Radeon RX560 (4gb) video
Sandisk 480gb SSD primary drive (250gb free)
Sandisk 1tg SSD secondary data drive (clean drive)
Thanks in advance for any advice!