What firmware have you gotten it to take?
I’m on the latest Dell one but I’d like to be able to standby/spindown drives.
Trying to crossflash to LSI firmware with EFI v14 results in "Failed to Validate Mfg Page 2!" as far as I can tell this is a check against the configuration data NVSRAM presumably to prevent crossflashing.
I tried modifying the sas3flsh.efi binary to bypass the check, it "worked" in that it said it flashed successfully, but resetting the adapter failed presumably because it never updated NVSRAM and there is a check at boot.
ManufacturingPage2 contains a copy of the SBR (missing the last 32 bytes – which appears to just be a repeat the first 32 anyway).
I found Scrutiny CLI (v20 from 2018) on the Broadcom FTP, which is useful for dumping the various memory regions and can provide some interesting information about the firmware image structure.
Scrutiny command support claims it can do lots of useful operations for SAS3 cards in Windows, Linux and UEFI compared to all the DOS/UEFI tools that are commonly used:
The cfg command displays, reads, writes, or resets various configuration pages and NVDATA settings. Page type options include: default, nvsram, and current.
The ul command uploads various images, such as firmware, BIOS, and flash, from the selected Broadcom HBA to a specified file. Make sure to use a proper binary file format.
The dl command downloads various images, such as firmware and BIOS, from a specified file to the selected Broadcom HBA.
If I’m feeling brave I'll try using some combination of the above the flash the stock LSI firmware, but I should probably figure out how to program the chips for when I inevitably brick the card.