Problem with PCIE sas passthrough with upgrade to PBE9

Aug 18, 2025
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Hi

I have a debian VM with direct access to 2 SAS adapters via PCIE passthrough
3b:00.0 Serial Attached SCSI controller: Broadcom / LSI SAS3008 PCI-Express Fusion-MPT SAS-3 (rev 02)
d8:00.0 Serial Attached SCSI controller: Broadcom / LSI SAS3008 PCI-Express Fusion-MPT SAS-3 (rev 02)

The firmware is 16.17.01.00. And according to Dell support it is the latest since 2020

Until PBS 9 (I used all version from 7.x to 8.4) there was no problem.

But with upgrade ti PBS 9, when I boot, it take a really long time and it blocks with


«Unable to load Avago Technologies MPT BIOS
MTP BIOS Fault 02h encountered at adapter PCI(00h,11h,00h)
Firmware Fault Code: 2667h»



The problem seems similar to this old bugreport
https://www.truenas.com/community/threads/is-rombar-1-important-for-truenas-vm.98242/


If i put rombar=0, the VM start without problem and I have access to my external disk bay.

What can I do ?

Is rombar option important ?

Thanks