BIOS halted with 0x06 Invalid Opcode in the pre-boot UEFI environment

[txr13]

I'm running OPNsense 25.7.11_2 on a Dell PowerEdge R250. After updating the BIOS to version 1.15, I can no longer boot OPNsense at all.

After POST, the loader menu comes up, and OPNsense proceeds to load the various modules for ZFS, intel_uucode.bin, bridge, and others I didn't catch. On a normally-booting system, the screen is cleared, the font changes, and the actual boot sequence begins. On a system running BIOS v1.15, I get a red screen indicating the BIOS has halted because of a CPU exception 0x06 Invalid Opcode in the pre-boot UEFI environment. Registers are visible, but there is no stack trace. (From memory, it says something about there being no LBR, but I don't know what that is.)

This was the primary router for a fairly large site, so I focused on getting the system back into operation rather than deeply investigating the issue. The problem was fixed upon reverting to BIOS v1.14.

Version 1.14 (working): https://www.dell.com/support/home/en-ca/drivers/driversdetails?driverid=t3jrr&oscode=naa&productcode=poweredge-r250
Version 1.15 (failed): https://www.dell.com/support/home/en-ca/drivers/driversdetails?driverid=2yt0g&oscode=naa&productcode=poweredge-r250

The most notable change in 1.15 seems to be "Intel processor and memory reference codes in the IPU Production Release IPU 2026.1 2125.15." I freely admit that I don't know that this caused the error, but I wanted to raise this as a possibility that this may change the opcodes available to the loader in the UEFI environment.

The site in question does have a secondary router on identical hardware, so there's a possibility I can use that to gather more information if necessary / helpful.

[meyergru]

I would guess that your OpnSense installation is a little older. You must know that OpnSense does never upgrade the actual UEFI bootloader.

Yours may be incompatbible with your current BIOS / microcodes in version 1.15.

So, once back to the running 1.14 release, you could try to manually upgrade the UEFI bootloader and then try again to upgrade your BIOS.

See this - not exactly your situation, but the instructions on how to update the boot loader probably still work. Patrick is the expert on these matters. Be careful about your specific partitioning.

[txr13]

I remember looking at that thread some time ago, as it happens! :) I was referencing it because I observed during the boot sequence that the loader needed to be updated. It was a while back, but I think the thread I saw was this one (https://forum.opnsense.org/index.php?topic=46035.0) which referenced your instructions to update the bootloader. (And in fact, I also remember taking some pains to be sure I updated the bootloader on both drives, since this is a ZFS mirror.)

So I know that the bootloader has been updated since the original installation, and probably within the last 12 months. It may be worth trying to update it again and then having a go with BIOS 1.15, but I do want to just confirm that I have done this update process once before in the past, so at the very least it's not as old as it could have been!