Mac Pro 5,1 firmware update for High Sierra

[Cave Man]

I have a Mac Pro 5,1 that is running Yosemite. I'd like to update to High Sierra; however, there's a firmware update that has be done beforehand. This is a work computer with specific software that has not been updated and is no longer sold that I have to keep functional. I will clone the hard drive with Carbon Copy Cloner in case I need to downgrade back to Yosemite to keep the software functional. However, I am concerned that the firmware update may prevent me from reverting back to Yosemite. Does anyone have information about whether the firmware update will break revision to Yosemite?

Details; 12-core processor, 128 GB RAM.

 

[Manzanito]

I have a Mac Pro 5,1 that is running Yosemite. I'd like to update to High Sierra; however, there's a firmware update that has be done beforehand. This is a work computer with specific software that has not been updated and is no longer sold that I have to keep functional. I will clone the hard drive with Carbon Copy Cloner in case I need to downgrade back to Yosemite to keep the software functional. However, I am concerned that the firmware update may prevent me from reverting back to Yosemite. Does anyone have information about whether the firmware update will break revision to Yosemite?

Details; 12-core processor, 128 GB RAM.

I can’t confirm Yosemite, but I can boot Snow Leopard with the firmware upgrade applied.

 

[tsialex]

You can safely upgrade your firmware, with the current one MP51.0089.B00 you can run even Snow Leopard if needed.

Mac Pro firmware does not restrict macOS versions that you can run.

 

[Cave Man]

Great, thanks very much.