Root volume renumbered unexpectedly, no longer boots

[Morgan Wesström]

> The SSD is on the mainboard controller.  I have no idea what the SATA
> controller's original mode was, but just now it was set to IDE.  I tried
> switching it to AHCI, but that didn't improve anything, and generated a new
> "AHCI BIOS not installed" error during boot, so I switched it back to IDE.
> Either of the RAID settings seem like bad choices, since I want direct
> access to the physical drives for ZFS.

I've seen systems that emulate 2-port master/slave controllers in 
IDE/Legacy mode and renumber drives differently in that mode than in 
AHCI mode.

That BIOS setting only affects the mainboard controller and with a 24 
disk ZFS pool I assume those disks are connected to some other 
controller. Regardless, I'd stay away from the RAID mode too though 
since there's a risk of overwriting some sectors of your system disk. It 
would've be interesting to know if that setting has changed though...

Is there any indication that the BIOS settings were reset during the 
disk swap? (Date/time being way off for example). Did you verify that 
the SSD is still connected to the lowest numbered port? ATA_STATIC_ID 
was removed back in 2015 if I remember correctly so unless you run an 
ancient FreeBSD version I wouldn't rely on that mechanism.

Perhaps you can tell us what kind of system this is in case someone on 
the list has a similar system and know its quirks. Also, if you're 
running a GENERIC kernel or not.

/Morgan