EPYC3451D412-2T reboot loop after bios udate

Hi,

I recently purchased a new EPYC3451D412-2T mainboard.
When I first started the board (with IPMI connection), I was able to access the IPMI gui and everything seemed to work. Sadly I couldnt access the BIOS settings after powering on, so I tried to update the bios via IPMI gui.

I used the bios file like described here:
https://www.asrockrack.com/general/productdetail.asp?Model=EPYC3451D4I2-2T#Download

Unfortunately the bios update didnt seem to work and didnt finish (the window was showing processing status from time to time but never finished).
Since that time I cant reach the IPMI gui anymore and I am stuck in a reboot loop. I can see in my network status, that IPMI is connecting for a few seconds. While a single power cycle I can even establish a connection with impitool in this ~5 to 10 second time window. Then it starts over and the connection is lost again.

Is there any way to get around this issue? Since there are no jumpers available to currently disable IPMI I cant come up with any solution to this.

I hope someone is able to point me to the right direction?! thanks in advance!