After properly building OVMF x64 with EDK2, the command:
qemu-system-x86_64 -s -pflash run-ovmf/bios.bin -net none
provides the following message
WARNING: Image format was not specified for 'run-ovmf/bios.bin' and probing guessed raw.
Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted.
Specify the 'raw' format explicitly to remove the restrictions.
This makes no sense to me as using qemu's -help command states "-pflash file use 'file' as a parallel flash image" where there is no parameter for a file format.
My OS is Windows WSL Ubuntu 22.04.1 LTS (GNU/Linux 5.15.79.1-microsoft-standard-WSL2 x86_64)
Qemu does still run, however I would like to run the VM without any write restrictions.
The '-pflash' option is (like -hda and -cdrom) a legacy "convenience" option which only allows you to specify a filename and nothing else. In order to specify other sub-options like the image format type, you need to switch to use a "long-form" option, which is typically some combination of -drive and -device. In this specific case, I think you probably want:
-drive if=pflash,file=bios.bin,format=raw