MP 1,1-5,1 Strange issue with flashing a 4,1 to 5,1

[aclarubicin]

So I've got this dual cpu 2009 tower, original gpu, ram and hdd with 10.11. Yet for some reason this tower refuses to be flashed to 5,1 using the known method. The current bootrom is the necessary MP4,1......B07.

Additionally, there is a firmware password set that I know, yet in recovery the startup utility says there is none. I'm able to set a new password and this is usable upon boot, but the utility keeps saying there's none set.

I've flashed a fair few towers myself but this one has got me stumped... anyone got an idea?


EDIT i’ve also disabled SIP

 

[MIKX]

It's been quite a while since I did the flash but from memory I seem to recall that I too was stumped until I put all the relevant files on the desktop.

 

[aclarubicin]

So just the two of them right, the efiupdate DMG and the flash tool?

 

[aclarubicin]

Dude this worked!

 

[MIKX]

Great ! 😀

Nice to know that I don't have Alzheimers !

You could keep a notebook titled " Solving cMP problems in case you buy another non-flashed 4,1 cMP.