Description of problem:
ovmf is taking a PMBR protective record's BootIndictor bit into account when
deciding whether the GPT is valid or not. When pmbr_boot (a.k.a setting a bit
on the protective record partition entry's BootIndictor in the PMBR, a.k.a.
setting the boot flag, a.k.a. setting the active bit) is set, the GPT is
seemingly considered invalid by ovmf and the system is not bootable.

Name-Version-Release number of selected component (if applicable):
ovmf-x86_64-202105-3.1

How reproducible:
Always

Steps to Reproduce:
1. Create a UEFI bootable image, boot it
2. parted /dev/vda disk_set pmbr_boot on
3. Try to boot the image

Actual results:
Firmware drops to an EFI shell.

Expected results:
It should boot.

Additional info:
Upstream bug has details including a test image attached:
https://bugzilla.tianocore.org/show_bug.cgi?id=3474

There is also now an upstream commit that can be backported to fix this:
https://github.com/tianocore/edk2/commit/b3db0cb1f8d163f22b769c205c6347376a315dcd