Note to self: do not update Intel Rapid Storage Technology drivers on a HP Proliant ML10v2, unless I really, really need to.
I've become complacent when throwing drivers at devices and this is a reminder how easy it is to break things. I recently added a TPM to one of my servers and one of the fixed drives is classified as removable by Windows, which means I can't use the TPM with it. There's at least two ways to fix this, either install Intel RST drivers and configure it through the console, or change some registry keys to force them to fixed drives.
So - download Intel RST version 126.96.36.1991 (the latest one that I thought was compatible), install, and reboot.
Restarting takes ages with a server BIOS, and you're unlikely to have it hooked up to a display, so I had to jump into the iLO console to work out why it hadn't started. After a reboot, all I had was the Windows logo, the spinning wheel, and shortly after a:
INACCESSIBLE_BOOT_DEVICE (we must restart)
Restarts will yield the same result, even on safe mode, I didn't have access to restore points, and the startup repair was also fruitless.
A fair while later I stumbled across this brilliant blog post which eventually provided success through:
Restoring an earlier driver version as per the post
Using the "Use last known good configuration (advanced)", which managed to remove the BSOD.
All in all, much of an evening wasted by a single driver.