Boot problem on DL380 G8

Hi, I have an old HP StoreEasy 1630 (basically an HP DL380 G8). I’ve replaced the Smart Array P822 with an LSI SAS9207-8i controller. The server has 12x3.5" drives in the front and 2x3.5" in the rear. The two rear drives are SSD, where I installed TrueNAS. The 9207 can see all the drives; I can check it in the SAS controller config utility (Ctrl+C during boot). But the problem is that I’m not able to boot from them. The booting ends up with a missing operating system message.
The actual bios on the SAS conroller is 7.39.00 and firmware 20.00.07.00. Thanks for any help.