HPE ML 30 gen 9 hangs when selecting Bios Legacy Mode boot type. How to overcome?

Question

System administration

Good afternoon. I ask for the help of the community, because unable to overcome on their own.
There is ml30 with 2HDD. It has a poor software b140 controller, which debian does not recognize and sees 2 mechanical hards. I switched the controller to HBA mode, I switch the boot to Legacy mode, because UEFI is not friendly with soft raid and the server hangs at the end of post.
Although, logically, after switching to legacy, it should be loaded once, i.e. post must pass and in the future it will be possible to select a device for booting, which the server itself reports when I switch the boot mode from UEFI to Legacy.
I downloaded the September SPP, updated all the firmware, and things are still there.
Help advice.