as a result of
@Surrat kindly putting his Mac Pro 4,1-5,1 on the front line with the risk of it being bricked.
I now have a nice easy "copy paste" method of adding the latest Nehalem and Westmere microcodes to any Mac Pro 5,1 BootROM
(theres a section/block in the Mac Pro BootROM where Microcodes sits it contains all the microcodes, I took this section deleted all the microcodes from inside this section, then pasted in the 2 updated microcodes inside this section then padded out the space after the 2 microcodes with FFs so the updated block matched the original blocks size, I then pasted the now updated Microcode section/block into the Mac Pro BootROM overwriting the original block, I verified the BootROM file size had not changed, then I sent the ROM to
@Surrat where he flashed it to his Mac Pro, where it looks like it has worked

)
having verified that it did not brick
@Surrat Mac Pro, I applied the updated microcode block/section to my own Mac Pro 5,1 which is my main machine, where it worked without any issues (this also "downgraded" my MP back to 0085)

its worth noting while this contains spectre patched microcode for Nehalem CPUs as well, that we have not tested Nehalem CPUs yet but
@Surrat will be doing that soon hopefully. he also Ran GeekBench on his Mac Pro where he reported no performance loss
hopefully this all makes sense, figuring all of this out was very hard and very stressful for me, as I was not just straight copy pasting overwriting stuff but I was also moving and removing data from inside the BootROM. if I had gotten just 1 byte wrong, Surrats Mac Pro could of well been bricked.
but now I have a file which I can just copy and paste into a Mac Pro 5,1 BootROM which will remove all old Microcode and insert the spectre patched Nehalem and Westemere Microcode

(also credit to
@dosdude1 for his nice little ROM flasher

)
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