X870E Nova Wifi code 00

Are you using a 9000 series X3D CPU?

Code 00 typically means CPU not found. You can try reseating the CPU as well as
double check your CPU 12v power connector.The issue could potentially be caused
by a dead or dying PSU.

If you are using an 9x00X3D then I would recommend you remove the CPU and check
it for any burned contact pads. If the CPU is damaged then you will want to
contact your retail outlet or AMD and begin the process of RMAing the CPU.
Once you receive a replacement you should then flash your BIOS to the latest
version. This isn't necessary if you are using a 7000 or 8000 series CPU however.

ASRock released an official statement on the 9kX3D issue here

A full list of your system specs would be helpful.

Looks like there isn't any obvious burning there, which I suspect would be the case
if the CPU died as a result of the issue I linked. I feel like there should be some
discoloration of the substrate (green PCB) if there has been excessive heat around
the power delivery pins.

Try using this method to fully clear your CMOS and see
if that helps at all. If not, then see if you can get your hands on another PSU
to test with.

Good luck

I am afraid I can only help out with boards I own when it comes to how things
come apart. Looking at the pictures on your product page it would seem the PCH
heatsink partially covers the CMOS battery holder, if so there must be a way to
pop it out without removing the PCH heatsink. There should be a spring catch that
holds the battery in, usually releasing that will cause the battery to pop up a
little then it can be slid out.

I doubt you will need 4 hours but it can't hurt anything. All that's needed is
for the clear CMOS pins to be shorted, you can use anything that achieves this.
Just be sure all power is disconnected from the system and that the caps have
been discharged (press and hold power button).

If that doesn't resolve the issue then I would recommend you open a ticket with
ASRock Tech Support.
They should be able to advise you regarding the CPU and any possibility it may
have been damaged. I wouldn't worry too much, AMD and ASRock have both been doing
everything they can to make things right with this issue. I am still hopeful this
isn't the case for you but it may be best to start the process incase.

The board indicates it shipped with 3.16 but I never verified or changed the version myself. I suppose its possible the company who assembled did flash it, but I doubt it.

My understanding is the flashback should work, but even the manual says to try removing the battery if doesn't.