The 2009 Mac Pro 4,1 Nehalem supports a maximum OS version of OS X 10.11.n or OS X 'El Capitan' to the rest of us. While El Capitan was a solid OS it was far from the best to come out of Apple and is getting a tad long in the tooth now. The good news is that these still very good Mac Pro 4,1 towers can be relatively easily upgraded to run macOS 10.14 Mojave and beyond, and serve many more years of service for you.
The first step of this, is to fool Apple's operating systems into thinking that your 2009 Mac Pro is newer and faster than it really is. We talk about hardware upgrades to newer faster 6 core CPUs and faster RAM in another chapter where you really can make your 2009 Mac to be a 2012 model or better. But first you need to upgrade the firmware.
While the 2009 Nehalem models were given a system designation of Mac Pro 4,1, the 2010 models that were identical other than the option for Westmere CPUs were provided a designation of Mac Pro 5,1. This model designation persisted until the 2012, it being the end of the line for the Mac Pro Tower till the 2019 model.
Apple still supports Mac Pro 5,1 machines up to macOS 10.14 Mojave, which means you can run the latest and greatest stable OS with a little hacking.
It is possible with a little tweaking of the installer to get Catalina to run on this hardware, but why would you? Catalina is pretty horrible on even a new 2020 machine, so much so in fact, that folks are hacking their brand new systems to run Mojave.
Its also possible to run Big Sur on your Mac Pro machine which is a lot more popular than its predecessor but it requires a lot more intervention. Both Catalina and Big Sur are also notably slower than High Sierra or Mojave.
Note
While the 4,1 to 5,1 firmware upgrade can be run on any OS version, to upgrade to 10.13 High Sierra AND receive the firmware updates, you need to be running 10.11.n 'El Capitan'. or 10.12.0 'Sierra' first. You can install a fresh version of 'El Capitan' on a freshly formatted hard drive from a USB installer BUT you will not receive the APFS firmware update! So don’t ditch that original 500GB Apple hard disk drive just yet!Before upgrading to macOS 10.14 Mojave, you need to update to macOS High Sierra 10.13.6 and then make sure that your graphics card is compatible. You also need to turn off FileVault. (See the Hardware Upgrade page for more details)
4,1 to 5,1 Firmware Upgrade
The first step is to take your perfectly working OS-limited Mac Pro 4,1 to make it look like a Mac Pro 5,1.This is by far the most finicky part of the whole upgrade process and uses a custom tool to install the 2010 Mac Pro 5,1 firmware on the 2009 Mac Pro 4,1 to make it appear to be 5,1.
There are multiple paths to nirvana here so you may have to try many before you reach your goal. I have had the most success launching this from an OS running OS X 10.10 Yosemite, but I have also had the process work using OS X 10.11 El Capitan.
First Disable SIP if trying this from El Capitan or Sierra
If you are running El Capitan or Sierra then you first need to disable SIP or 'System Integrity Protection' in order to run the unsigned firmware installer (Older OS versions weren't afflicted with SIP, so you don't need to worry if you're running 10.9 'Maverick' or 10.10 'Yosemite'. If you want to read the 500 word article all about SIP and how to disable it / re-enable it then read this Mac World article on the subject. If not follow the 'to the point' instructions below:First, power off your machine till fully off, then power on holding down Control+R to boot into Recovery Mode.Now go to Utilities and open a Terminal window.Type 'csrutil disable' then hit enter. Terminal should display a message that SIP was disabled.
You can then type 'reboot' in the terminal window then hit enter to reboot back to your current installed version.
Upgrade the EFI Firmware
You will need to download the Custom Firmware tool and the Mac Pro 5,1 EFI firmware to upgrade to 5,1 firmware and save both on your Mac Pro.
As an alternative you could download the installer package from Mac Rumors but it only appears to run on OS X 10.9 and OS X 10.10.) Hence I extracted the installer app from the package and have made it available on our servers. As Apple may remove the MP51.007F.B03 firmware I also have that saved for posterity.
Unzip the both files file to your desktop or somewhere of your choosing. You should see the file 'MacPro2009-2010FirmwareTool.app' and 'MacProEFIUpdate1.5.dmg'. Open the firmware update but do not run the pkg. We are going to use the custom tool to do that. Now run the 'MacPro2009-2010FirmwareTool.app'
You may need to change your Security and Privacy settings to allow an unsigned application to run, in which case go to System Preferences / Security & Privacy and make the necessary changes.
Now you should be able to run the Mac Pro 2009-2010 Firmware Tool.
Follow the onscreen instructions.
Shut down, (do not restart).
Once completely powered off, press and hold the power switch. You will need to hold until the little light above the power button begins to flash, release power button and you should hear a long tone.
Wait for the grey screen with Apple logo and progress bar (this is the upgrade working), it will reboot automatically once done.
Your upgrade is complete. Now Check your System Report to be sure it worked? Go to 'About This Mac'. You will note that the machine designator still says 'Mac Pro (Early 2009)' - that's fine - it's just cosmetic.
Click on System Report and check the following screen. It should have changed the 'Model Identifier' to 'MacPro5,1' which means that you can now run faster CPUs, faster 1333 Mhz RAM, and upgrade your OS to 10.12 Sierra and beyond.
Once you are running firmware to say you now have a Mac 5,1 you can power off and upgrade CPU and RAM (see the section on hardware upgrades). You can also install your OWC Mercury Accelsior NRAM system volume or another PCI based drive system and install a clean version of 10.12 Sierra)
To upgrade to Mac OS 10.13 'High Sierra' download the installer and copy it to your Applications folder and run the upgrade from there. The first step will be to perform another firmware upgrade. Follow the instructions, shut all the way down then hold the power button till the light flashes then release to perform the firmware update. The installer will reboot to apply the new firmware and continue to install the new OS. Approximately 45 minutes later you should have a running version of 10.13 'High Sierra' with an updated Boot ROM Version (Compare images above and below)
To update to 10.14 'Mojave' you will need to first apply the 10.13.6 'High Sierra' update from the Updates in the App Store. You also need to turn off FileVault.
10.13.6 is a large update that changes a lot of things and adds a lot of new features so be prepared for a lengthy download and even longer install. In fact applying the 10.13.6 patch is longer than the upgrade between full operating systems.
The Mojave installer REQUIRES that all video cards support ‘Metal’, an Apple technology that lets the system and apps efficiently tap into the capabilities of today’s graphics processors (GPUs). The graphics cards offered by Apple in any version of the Mac Pro don't have GPUs that support Metal, so these systems require upgraded graphics cards in order to install macOS Mojave. This means that you cannot simply pop in your old Apple GT120 or Radeon 4870 Apple video card to observe the firmware upgrade process but have to do it blind unless you have an Apple EFI supported video card meeting the Metal requirement.
What most people do is to borrow or purchase a regular PC Radeon RX 560/570/580 card as it avoids the need for additional drivers for an nVidia GeForce since most Apple systems run Radeon video cards. However the PC video card will not provide EFI boot support for Apple systems which means you will not be able to see the system booting up or any error messages.
I did my 'Mojave' install / firmware update blind with a non-EFI card. Simply follow the instructions to shut down and power off, then hold down the power button till the light flashes on and off and you hear the firmware upgrade tone. Leave the system to update the firmware till it shuts down fully. When you power on for a third time the Mojave installer will continue. You will be able to observe the install on your non-EFI card - just not the firmware update.
After the firmware has been updated check your System Report to validate that the Boot Rom has been updated yet again.
The Mojave installer should restart prompting you to Continue with the install.
Once 'Mojave' is installed you can simply reinstall your Apple EFI video and do without the metal features, and keep the Apple card for troubleshoot boot problems if any arise in the future. This works for the Apple ATI Radeon 4870 video card which was standard with dual CPU / 8 Core 2009 Mac Pros and an option for the single quad core system, most of which were fitted with the GT120 by default. The GT120 simply doesn't cut it today. Of course if you plan to use the Mac Pro connected to a 70" TV screen then you will want to purchase a more more powerful Radeon 560/570/580/590 or better system anyway.
Once you have 'Mojave' installed with its firmware update, you can continue upgrading any hardware. You must however install an SSD drive or NRAM OWC Mercury Accelsior PCI Card BEFORE upgrading to 10.14 (see above).
Unzip the both files file to your desktop or somewhere of your choosing. You should see the file 'MacPro2009-2010FirmwareTool.app' and 'MacProEFIUpdate1.5.dmg'. Open the firmware update but do not run the pkg. We are going to use the custom tool to do that. Now run the 'MacPro2009-2010FirmwareTool.app'
You may need to change your Security and Privacy settings to allow an unsigned application to run, in which case go to System Preferences / Security & Privacy and make the necessary changes.
Now you should be able to run the Mac Pro 2009-2010 Firmware Tool.
Follow the onscreen instructions.
Shut down, (do not restart).
Wait for the grey screen with Apple logo and progress bar (this is the upgrade working), it will reboot automatically once done.
Your upgrade is complete. Now Check your System Report to be sure it worked? Go to 'About This Mac'. You will note that the machine designator still says 'Mac Pro (Early 2009)' - that's fine - it's just cosmetic.
Click on System Report and check the following screen. It should have changed the 'Model Identifier' to 'MacPro5,1' which means that you can now run faster CPUs, faster 1333 Mhz RAM, and upgrade your OS to 10.12 Sierra and beyond.
Second Firmware Upgrade
As part of the UPGRADE installer for Mac OS 10.13 'High Sierra', there is another firmware update to enable APFS and other new features. To receive this you MUST upgrade from 10.11 or 10.12 to 10.13 as explained above. A fresh install will allow you to run 10.13 but not APFS or any of the other features. Nor will you be able to upgrade to 10.14 'Mojave'. If this is what you did, you will need to go back install a version of 10.11 or 10.12 and then upgrade. I found an extracted version of just the firmware update in one of the forums but couldn't get it to run.To upgrade to Mac OS 10.13 'High Sierra' download the installer and copy it to your Applications folder and run the upgrade from there. The first step will be to perform another firmware upgrade. Follow the instructions, shut all the way down then hold the power button till the light flashes then release to perform the firmware update. The installer will reboot to apply the new firmware and continue to install the new OS. Approximately 45 minutes later you should have a running version of 10.13 'High Sierra' with an updated Boot ROM Version (Compare images above and below)
Third Firmware Update
10.14 'Mojave' requires yet another firmware update. Like 10.13 the firmware update is built into the OS UPGRADE installer. This means that you cannot perform a clean install of 10.14 on a Mac Pro - either install 10.12 and upgrade, or run the upgrades and firmware updates to 10.13.6 then perform a clean install of 10.13.0 before upgrading to 10.13.6 and on to 10.14.To update to 10.14 'Mojave' you will need to first apply the 10.13.6 'High Sierra' update from the Updates in the App Store. You also need to turn off FileVault.
The Mojave installer REQUIRES that all video cards support ‘Metal’, an Apple technology that lets the system and apps efficiently tap into the capabilities of today’s graphics processors (GPUs). The graphics cards offered by Apple in any version of the Mac Pro don't have GPUs that support Metal, so these systems require upgraded graphics cards in order to install macOS Mojave. This means that you cannot simply pop in your old Apple GT120 or Radeon 4870 Apple video card to observe the firmware upgrade process but have to do it blind unless you have an Apple EFI supported video card meeting the Metal requirement.
I did my 'Mojave' install / firmware update blind with a non-EFI card. Simply follow the instructions to shut down and power off, then hold down the power button till the light flashes on and off and you hear the firmware upgrade tone. Leave the system to update the firmware till it shuts down fully. When you power on for a third time the Mojave installer will continue. You will be able to observe the install on your non-EFI card - just not the firmware update.
After the firmware has been updated check your System Report to validate that the Boot Rom has been updated yet again.
Once 'Mojave' is installed you can simply reinstall your Apple EFI video and do without the metal features, and keep the Apple card for troubleshoot boot problems if any arise in the future. This works for the Apple ATI Radeon 4870 video card which was standard with dual CPU / 8 Core 2009 Mac Pros and an option for the single quad core system, most of which were fitted with the GT120 by default. The GT120 simply doesn't cut it today. Of course if you plan to use the Mac Pro connected to a 70" TV screen then you will want to purchase a more more powerful Radeon 560/570/580/590 or better system anyway.
Once you have 'Mojave' installed with its firmware update, you can continue upgrading any hardware. You must however install an SSD drive or NRAM OWC Mercury Accelsior PCI Card BEFORE upgrading to 10.14 (see above).
