There are three LSI MegaRAID controllers used, two 9260-16i for 16 drives each (sb_data_?), one 9280-24i4e for 24 drives used also for boot and meta (sb_data_?, sb_system, sb_meta).
If the cards had been changed out or other PCI cards added the BIOS might change and system might not boot from the correct device.
Go into the MegaRAID BIOS, press control H during POST after reset/reboot/power on.
Make the appropriate "Set Boot Drive" setting on each Virtual Drive on each controller, only the system boot RAID 1 pair should be set.
Enable the BIOS of the controller containing the system boot RAID 1 pair, disable the other. Go to each controller and then Controller Properties > Controller BIOS.
Exit MegaRAID BIOS.
Enter system BIOS, press DEL during POST.
Select BOOT tab, select RAID as the boot device in "Hard Disk Drives" and "Boot Device Priority", there should only be one RAID option.