Hello. I had a same issue on VRTX after changing mainboard and CMC. Both PERC8 RAID controllers were not visible in Storage>Controllers overview. I can confirm that this solution above works. My steps: 1. Updated CMC card to the latest firmware version available 3.41 2. Configured CMC and iDRAC IP address settings 3. RAID controllers still not visible 4. Powered VRTX off, disconnected power, removed chassis cover, performed "power flea" by holding power button for 15-20 sec 5. Changed place of CMC card from SLOT1 to SLOT2 (I have only one CMC installed, if you have two, switch their place)
6. Switched places for PERC8 controllers (hint: controllers should blink green light after power on) 7. Booted, checked IP config, opened web interface and both PERC8 showed up!
Huge thanks to @stroebs for sharing the solution, you saved my day!