This comes as a response from Techpowerup's discovery that Radeon VII does not have UEFI-ready BIOS, and while it is not a big issue, it does make a boot slower than with the UEFI-ready BIOS. Some reports online also suggest that Radeon VII was not really missing UEFI BIOS support but rather just an "info-flag", but nevertheless, all should be fixed with the upcoming simple BIOS update.
ASRock was the first to release the BIOS update and it pretty much works on any Radeon VII graphics card but the official one from AMD should come soon.
"AMD has released a BIOS for the Radeon VII with UEFI GOP included for our AIB partners. We will also make a one click installable BIOS available to end users via AMD.com. We do not expect gaming performance differences between the non UEFI BIOS and the UEFI GOP included BIOS, although the non UEFI BIOS may experience slower boot times from cold boot."
Those that managed to buy a Radeon VII graphics card should be on the lookout for AMD's official BIOS update and update it accordingly.