I just went through the process myself and none of the guides I found worked for me by themselves. But, if you combine them all and do a little research on your own it does work. The things that bit me are: uefi bios requiring booting to usb then booting to uefi shell then ... and the fact that I wanted to boot from the controller so I had to go find the bios and none of the packages had the bios and many of the places had the wrong one
Updated: SAS HBA crossflashing or flashing to IT mode, Dell Perc H200 and H310 is pretty close to what I ended up with and covers the UEFI issue very well.
hint: you need to use "sas2flsh -o -b mptsas2.rom" after updating the firmware if you want to boot from the card. You can not combine the -f <file> and -b <file> on the same line like some guides suggest, or at least it didn't work for me.
hint2: find a machine without a UEFI bios to do the flashing and you will save yourself a LOT of time. You can do it with a machine with a UEFI bios. I did. But everyone says it is a lot faster to find without UEFI getting in the way.
Your card "may" have the SAS address on a label if you forgot to write it down. If not, you can make one up like the guides suggest.
5000 + the output from "openssl rand -hex 6" should work.
Finally, did you cut / cover the i2c lines? I think I read that some motherboards won't boot if they are left alone. Mine don't care so I didn't bother.