MP 1,1-5,1 Mac Pro 4,1>5,1 High Sierra firmware update fails

[myoheddie]

Hey everyone,

as per the title, my (new to me) 2009 (flashed to 5,1) is refusing to let me install High Sierra, asking for a firmware update. The Update button is greyed out, and I've tried using the holding down the power button to force and update, but just the long beep and straight into normal boot. Am I missing something here? Are 2009's just not getting the update, or is mine being odd?

Using a standard GT120 and no PCIe cards or SSDs.

Thoughts?

 

[tsialex]

Hey everyone,

as per the title, my (new to me) 2009 (flashed to 5,1) is refusing to let me install High Sierra, asking for a firmware update. The Update button is greyed out, and I've tried using the holding down the power button to force and update, but just the long beep and straight into normal boot. Am I missing something here? Are 2009's just not getting the update, or is mine being odd?

Using a standard GT120 and no PCIe cards or SSDs.

Thoughts?

Did you read the first post of the thread MP5,1: What you have to do to upgrade to Mojave (BootROM upgrade instructions thread). Fully read it, pay attention with the notes since there are several pitfalls with firmware upgrades. Check everything.

A MP4,1>5,1 can be upgraded up to MP51.0089.B00, this is the last High Sierra BootROM for MP5,1, when using the original video card (NVIDIA GT 120/ AMD 4870) and up to 144.0.0.0.0 (current Mojave BootROM) with a METAL supported one.

Start from a clean install of El Capitan/Sierra, since both can run without a firmware upgrade.