Most of the time we get to update the BIOS, factory reset the BIOS, change the BIOS to our settings then install the OS just like we did way back when.

I used to try to save the OS but as time is a factor and clients have not wanted to pay for that service we no longer do that work.

As to the RAID, when the motherboard changes you often find yourself setting up the RAID from scratch and restoring from backups.