Error code 0d

Trying to boot a new Asrock Gaming X x570 motherboard but I keep getting a 0d error code.
My understanding is this code indicates a problem connecting USB, PCIe, video card, RAM devices.
I have removed all PCIe connections including the M.2 SSDs, have disconnected all the USB headers, have removed the wireless mouse USB connector, have removed and reseated all the RAM (I have four 8GB Thermaltake sticks) and then reduced them to only the A2/B2 slots and then swapped sticks, have removed and reseated the video card and when that did not change things I replaced it with an older card I know is functional.
Nothing has gotten the boot process past the 0d error code.

Update:
Have removed all devices, RAM, video card, etc. Only connections are power and the Front connections (Pwr switch, reset etc.)
The first error code is A6 (SATA issues but none are connected) then goes to 0d error and no further progress.

CPU is Ryzen 5 5600x|ASRock X570 Phantom Gaming X.

Have not removed motherboard to test boot outside of case, but this sounds like a dead board to me.

Test outside the case using a screw driver or similar to short the power pins to start up system .. or try shorting pins before you pull out of case and remove the front panel power/reset connectors.

I had the same problem with a new build (error code 0d and no display output) until yesterday.

Configuration:
ASRock X570 PG Velocita
AMD Ryzen 9 5900X
ASRock Radeon RX 6500 XT PG
TeamGroup T-Force Vulcan Z DDR4-3200

What did not work:
I had the 2?32 GB RAM modules in slots A2 & B2, per instructions. I tried to boot with the factory-installed BIOS because of warnings not to upgrade working MoBos, but it did not work. I updated to the new beta version, 5.01, released one week prior, and reset the CMOS by removing the battery for at least 5 min (I put in a new battery) and holding down the CMOS reset and power buttons for 30 s. However, the boot process still ended at code 0d. I read multiple forums that recommended trying to boot with every possible combination of each RAM module in each slot. I removed the module from B2, but it still stalled at 0d.

What did:
I moved the RAM to slot A1 (only one module installed) and booted up, pressing F2 to enter UEFI setup. In the "OC Tweaker" section, I changed the "Load XMP Setting" from "Auto" to "XMP 2.0 Profile 1: DDR4-3200 16-18-18-38 1.35 V". The "DRAM Frequency" automatically changed to "DDR4-3200" and the "DRAM Voltage" to "1.350". I saved the settings and rebooted with the second module in slot B1 (I did not want to move the working one). Then I was able to install Linux Mint and utilize all 64 GB of RAM.