i have same problem on Thinkpad X1 Carbon Gen 6 using Fedora 35 (latest) when i disable Secureboot and run fwupdmgr upgrade and reboot then it waits for a minute and then reboot into grub again.
only ME update is failing for me, i have sent debug info from fwupdmgr.
I managed to upgrade bios using fwupdmgr update <Device ID>
i have same problem on Thinkpad X1 Carbon Gen 6 using Fedora 35 (latest) when i disable Secureboot and run fwupdmgr upgrade and reboot then it waits for a minute and then reboot into grub again.
only ME update is failing for me, i have sent debug info from fwupdmgr.
I managed to upgrade bios using fwupdmgr update <Device ID>