Guide to Flashing 2009 Xserve XS3,1 with 2010 Mac Pro MP5,1 Firmware: Xserve 3,1 Westmere Support

The 2009 Apple Xserve, also known as the Xserve 3,1 (XS3,1), never supported the Intel Westmere Xeon family. However, the 2010 Mac Pro, Mac Pro 5,1 (MP5,1), did. Since their logic boards are similar, you can flash your XS3,1 with the MP5,1 firmware. This will enable you to use 6-core Westmere Xeons and after the flash the most powerful one you will be able to install is the Intel 6-core 3.46 GHz X5690. Without this flash, the most powerful Xeon you can install in the machine is the Intel 4-core 3.33 GHz W5590.

Loss of the ability to boot from the USB port on the front of the machine.
Inability to configure LOM.
When using macOS (formerly OS X), you will lose 2 memory slots and the machine’s serial number.

Known Issues

While this sounds promising, there are some drawbacks. However, the macOS related ones can be generally solved using the OpenCore bootloader.

MacOS Only:

Loss of 2 memory slots.

All Operating Systems:

Inability to boot from a USB on the front panel (though it can be used post-boot).
Loss of target disk mode.
Loss of the ability to configure LOM.
Loss of serial number. The serial number can be re-flashed onto the machine using the Apple Blank Board Serializer or injected via OpenCore. If you didn’t keep the serial number it can be found on the grey pull tab in the back of the machine along with the Mac addresses of the ports for the onboard network card.

Benefits

The primary reason for the flash is to gain support for Intel Westmere CPUs with 6 cores instead of 4. However there are other benefits as well:

Boot from APFS file system
Boot from NVME drives

Flashing the Machine

DISCLAIMER: This involves firmware, and errors can render the machine useless. Only attempt this if you’re willing to take that risk and possess the technical knowledge to execute it correctly. Ensure the machine doesn’t lose power during the process. If possible, use a battery backup and avoid performing this during unstable weather conditions.

These instructions were developed and tested using a USB drive that had 2 partitions, the first was the El Capitan installer and the second was El Capitan. However, they should work with any setup that has a macOS version that runs on the XS3,1 and the corresponding recovery partition.

Obtain the MP5,1 firmware
1. Download the Mojave installer directly from Apple, as it contains the MP5,1 v144 firmware (last and most recent version of MP51 firmware) needed for the flash. You can download it here, https://support.apple.com/en-us/HT211683
2. Extract the MP5,1 firmware file located at Install\ macOS\ Mojave.app/Contents/Resources/Firmware/MP51.fd. To be able to use it you will need to change the file extension from .fd to .bin so if you would like for better clarity you can rename it as MP51_v144.bin or just do MP51.bin but either you will need to change at very least the file extension to use it later on.
Backup your Firmware – DO NOT SKIP THIS STEP!
1. Download the Dosdude1 EFI firmware flashing tool here and use the password “rom” to extract the ROM tool.
2. Open ROMTool.app (you might need to adjust system preferences to allow it to open) and click “Dump System ROM”.
3. Name the resulting file something memorable, like XS31.bin as this is your current XS3,1 firmware
Configure Lights Out Management (LOM) – DO NOT SKIP THIS STEP IT CANNOT BE DONE POST-FLASH!
1. Open either the Server Monitor App or Luminous LOM Configurator.
2. If using the Server Monitor App, navigate to Server > Configure Local Machine.
3. Optional – Reset the current settings with port 1 selected. Switch to port 2 and click reset again.
4. Set your network and user setting then ensure you can connect to the LOM remotely, not just locally with 127.0.0.1.
Flash the MP5,1 firmware:
1. Disable System Integrity Protection: Shutdown and boot into the recovery partition or corresponding macOS installer. Go to the Utilities menu, select Terminal, and run the csrutil disable command. Then shutdown the machine.
2. Boot in firmware flashing mode: After having the machine shutdown for at least 15 seconds, press AND HOLD the power button until the white power light flashes rapidly, then release and allow to boot normally. If while holding down the power button the machine starts and then shuts down again, release the button and try again until you observe the rapid flashing. You may have to do this a few times to get it to work. If the power light doesn’t flash, the firmware flash WILL NOT WORK.
3. Flash the firmware: After starting the machine into macOS open ROMTool.app, and click “Flash System ROM”, then select the “MP5,1.bin” file or whatever you changed the name to in step 1 and wait for a notice that the flash is complete.
4. Reboot the machine
Confirm the firmware flash:
1. Depending on the macOS version you used used for the flash, you might need another macOS install to boot into. For instance, a newly flashed machine might not boot back into El Capitan once flashed. You may also need to use the OpenCore Legacy Installer to install the OS you want to use or setup the the OpenCore bootloader as needed.
2. To confirm the firmware did indeed get updated you will need to access the System Profile and ensure the bootrom version is 144.
3. The “About This Mac” screen will also show a missing serial number and identify the machine as a Mac Pro. The memory screen will also show the 2 missing memory slots even when all slots are populated.

Frequently Asked Questions

How do I know if this flash is for me?
The primary reason for the MP5,1 flash is to use Westmere 6-core chips. However, consider the drawbacks listed in the Known Issues section.
Is it difficult?
No. Following this guide should make the process straightforward, even for novices.
Do I need a Westmere Xeon Chip(s) to do the flash?
No, you can use the factory Nehalem chips with the flash, but there isn’t a lot of benefit. However, once flashed you can swap out the Nehalem chips for the Westmere chips.
Can I revert to the original firmware?
Yes, although it hasn’t been personally verified. You can restore the XS3,1 firmware even without a backup. Refer to the troubleshooting section for more details.

Troubleshooting

The system profiler doesn’t show 144 as the bootrom!
Ensure the XS3,1 is in firmware flashing mode. Revisit the steps and ensure the power light flashes rapidly when starting the machine.
I lost my ROM backup and want to revert!
Obtain the original XS3,1 firmware from Apple here. Follow the flashing steps above to revert your Xserve. Remember, you might still need to update your firmware to the final version (B09) of the XS3,1 firmware.