ROMED8-2T doesn't boot anymore

Hi,

I own a ROMED8-2T motherboard and since a recent reboot of the machine, it won't boot nor show any video signal on an external monitor. The IPMI ethernet port flashes but doesn't get a DHCP address. The BIOS screen shows b2 code.

Here's what I did to troubleshoot the problem :
1. Stripped down the computer to the basic (CPU + RAM only, nothing else)
2. Alternated the position of the RAM
3. Reinstalled the CPU in case there was an alignment problem
4. Tested with only one RAM stick

Still got b2 code. Then :
1. Temporarly bringed back everything together
2. Removed CMOS battery + shorted CMOS
3. Started back on the computer

Now, the BIOS screen shows a 90 sec countdown and end up with a b2 code. Here's a video of the BIOS screen in case it shows useful informations : https://we.tl/t-oQ0BDmrziS

Finally, here's the whole setup :

Motherboard Model Name :
ROMED8-2T
CPU/Processor (Brand,Speed, FSB,Cache Size)
AMD Epyc 7302P, 3.0GHz, 128 MB
Memory (Speed, Capacity, Brand)
DDR4 3200 (PC4 25600), ECC Registered, 64 GB, Micron
Video Card (Brand, Model, Memory size)
MSI, Radeon RX Vega 56 xAir Boost, 8G
Operating System (Loaded service pack and driver)
TrueNAS Scale v23
Hard Drive (Brand, Model, Capacity)
Seagate IronWolf, ST16000NTA0, 16TB
Other Device (Brand, Model)
2x NMVe SAMSUNG 980 PRO SSD 500GB
2x NVMe SAMSUNG 980 PRO SSD 1TB on 2x NVMe to PCIe 4.0 X4 Adapter
Gigabit Ethernet (Intel I210-T1)

With these infos and your valued knowledge, is there anything that can be done to fix this issue?

Thanks in advance and regards!

This may be of help:
https://forum.asrock.com/forum_posts.asp?TID=11132