Let me start this post with a very clear disclaimer here.
I documented everything needed to clean up, upgrade and downgrade MP5,1 firmwares in the last three years. If you follow the rabbit hole, you can create clean a NVRAM volume, MP4,1 and MP5,1 MLB/LBSN sectors (they differ with the jump points, you can't use a MP4,1 MLB/LBSN sector with a MP5,1 firmware or vice-versa, will be a brick) and provided detailed instructions on how to repair bricks. You can even upgrade a NVRAM hardware descriptor from MP4,1 to MP5,1 changing the Base_xx (17, 18 and 19 for MP4,1 - 20 and 21 for MP5,1) with my posts. For years I cleaned, upgraded and reconstructed BootROMs for free, I did more than three hundred, but since my time is now very restricted and people abused my goodwill to the extreme, now I only do it as a contract service and by PM.
MP4,1 and MP5,1 BootROMs are more than just the firmware. Apple designed the Mac Pro to use one SPI flash memory for all these things, simplified a lot for easy comprehension:
- the EFI firmware,
- the NVRAM,
- the BootBlock,
- to store the hardwareIDs, where you differentiate one Mac from another.
MacEFIRom script from Netkas forum use Apple efiflasher toolkit to upgrade your Mac Pro BootROM from a MP4,1 to a MP5,1 firmware. It works with some caveats:
- Don't work with MP41 B08 firmware, it expects that you have a B07.
- Only works with earlier macOS releases, 10.6 to 10.9, SIP and recent macOS security improvements severely constrain the use of the script.
- Only upgrades the EFI Firmware. The NVRAM, BootBlock and hardwareIDs are kept exactly the same. So you have a hybrid that won't work for Firmware Restoration CD, for example, since your still have a MP4,1 BootBlock with a MP5,1 EFI firmware. That's why we usually call these hybrids as MP4,1>5,1.
My quick and dirty instructions
are a improvement over the script and the result will be a MP5,1 firmware, still with MP4,1 NVRAM but now with a MP5,1 BootBlock. Firmware Restoration CD 1.9
(MP5,1 version) can be used, if needed.
I don't like to explain this topic much, since some people will think that I'm advertising a service, but a complete upgrade from MP4,1 to MP5,1 can be done. It involves more things, like the total clean up of 1st and 2nd stores, upgrade of the 3rd store of the NVRAM from MP4,1 override versions (the hardware descriptor) from MP4,1 versions (Base_17 to Base_19 for normal MP4,1s and Base_20 for B08 2009 Mac Pros) to mid-2012 standards (Base_21 override version from late manufactured mid-2010 and all mid-2012) and correction of several checksum hashes to make everything valid.