With that said, some of the guides I've used call for using megarec to wrote zeros to the sbr and clear the flash before proceeding.
I tried megarec very late last night. It worked under FreeDOS. I then rebooted to EFI, and tried to flash the P14 firmware with sas2flash.efi .
Unfortunately, the firmware failed to boot in an identical way.
Also, I know for one of my cards, it absolutely refused to update an existing crossflash with P20. The solution I found online (again, not figured out by me, I'm not that smart!) was to USE AN OLD VERSION OF TOOLS to use megarec to writesbr with 0s and then cleanflash. Then again with OLD VERSION TOOLs flash to P14 IR firmware, then crossflash to P14 IT firmware again with old tools, and from there use the CURRENT tools to update the P14 IT firmware to P20 using the regular process. Sounded kind of stupid and painful and pointless to me when I read it. But it worked and didn't take long.
I used FreeDOS via Rufus for the DOS parts, and switched to EFI for the actual firmware flashing.
EDIT: as I recall, the original poster's explanation for using old tools was that the P20 toolset had a problem fully clearing the flash of an HP branded card. P14 was more easygoing and worked better to wipe the flash apparently. I notice your card in the photos had an HP sticker on it.
The P14/P20 packages only contain tools for DOS and Windows. They don't contain any EFI flasher.
I have flashed DOS onto a USB stick with Rufus already. The DOS sas2flash tool doesn't work at all on most current UEFI motherboards, even when enabling CSM. In DOS, I get the "ERROR: Failed to initialize PAL. Exiting program.". I can't even list the card. The error happens even when running the program without any argument.
From what I have gathered through Google searches, the DOS version of sas2flash requires a service called "BIOS32 directory" to be implemented in the BIOS in order to be able to run.
See
SOLVED - SAS2FLASH Easier Alternative .
This support is missing from all of my motherboards. Thus, I cannot flash in DOS.
The Windows version of the flash tool doesn't see the card at all. I see that the LSI driver fails to load in Device manager, probably because the firmware is missing.
The only tool I have that allows flashing is sas2flash.efi . Are there multiple versions of that ? It looks like there might be, so I'm going to look for those. However, so far, every post I have found through Google of someone who successfully recovered the card in this state has done so using FreeDOS.
If I'm reading correctly, to have any hope of recovering my card, I would need :
1) FreeDOS
2) The P14 or older version of sas2flash.exe for DOS
3) a motherboard that supports the BIOS32 directory service, probably a non-UEFI board >10 years old
Unfortunately, I don't have anything that meets the 3rd requirement.
I'm going to look for older sas2flash.efi now, and pray that this works.