Working around HBA option ROM boot failure

One of my servers rebooted due to unexpected power failure, and after the power came back up, it tried to boot, but looped in HBA option ROM. A disk failed before that and I did not manage to take it out. I guessed that was the reason, but my server was at remote and I did not have physical access. I preferred to work around it remotely.

The server did have virtual CD-ROM and KVM feature (although it requires ancient version of Java on browsers, which is painful), and by that, I booted an ISO to get a working temporary Linux environment for inspecting the situation. To boot with virtual CD-ROM, I needed to skip the HBA option ROM loop via CTRL+C before that to make it not to try booting and go to its settings utility instead. With the temporary Linux environment, I checked that all the previously working disks are fine, and should be able to boot it if I loaded the kernel and initrd from something that did not go through the HBA.

Initially, I thought using an external GRUB from an ISO to load kernel from disk may work, and experimented with grub-mkrescue. GRUB did not seem to recognize any disks, which made sense without a dedicated driver for the HBA. I then tried to pack kernel and initrd into the ISO, but booting them got me a 452: out of range pointer.

Then I tried ISOLINUX. Creating a kernel-loading ISO with it was easy and straightforward. Booting with it worked perfectly. This workaround works except that I might need to wire up the virtual CD-ROM again if it needs to boot another time.