In case anyone needs working instructions for flashing Broadcom (LSI) 9500-8i HBA inside TrueNAS Scale, here’s easy instructions.
./storcli64 show (to see current firmware)
./storcli64 /c0 download firmware file=HBA_9500-8i_SAS_SATA_Profile.bin. (or HBA_9500-8i_Mixed_Profile.bin depends on the mode)
./storcli64 /c0 download bios file=IT_HBA_X64_BIOS_PKG_E6.rom
./storcli /c0 download psoc file=pblp_catalog.signed.rom
Shutdown & reboot, to make sure you flashed it, run ./storcli64 show again.