4,1 MacPro upgrade

[Markintosh]

Hi Gang!

I'm interested in bringing my '09 Pro past OS 10.11

I understand flashing the firmware can make the Pro "think" it's a 5,1 - therefore getting past the 10.11 install limit.

I have an old i7 iMac that died due to the graphics card failure we're all familiar with.

I installed the iMac HDD into my 4,1 to retain the data on the iMac.

One day I booted from the iMac HDD and, to my surprise, my unmodified 4,1 was running 10.13!!

My question is: Have I bypassed the NEED of upgrading my firmware if 10.13 can boot? I did not run exhaustive tests-can I run with this HDD without any issues?

Does anyone have experience with this?

Thanks in advance!

--Mark

 

[Nixontheknight]

Hi Gang!

I'm interested in bringing my '09 Pro past OS 10.11

I understand flashing the firmware can make the Pro "think" it's a 5,1 - therefore getting past the 10.11 install limit.

I have an old i7 iMac that died due to the graphics card failure we're all familiar with.

I installed the iMac HDD into my 4,1 to retain the data on the iMac.

One day I booted from the iMac HDD and, to my surprise, my unmodified 4,1 was running 10.13!!

My question is: Have I bypassed the NEED of upgrading my firmware if 10.13 can boot? I did not run exhaustive tests-can I run with this HDD without any issues?

Does anyone have experience with this?

Thanks in advance!

--Mark

you can push it even further with OpenCore Legacy Patcher

 

[phunguss]

I understand flashing the firmware can make the Pro "think" it's a 5,1 - therefore getting past the 10.11 install limit.

I have an old i7 iMac that died due to the graphics card failure we're all familiar with.

I installed the iMac HDD into my 4,1 to retain the data on the iMac.

One day I booted from the iMac HDD and, to my surprise, my unmodified 4,1 was running 10.13!!

My question is: Have I bypassed the NEED of upgrading my firmware if 10.13 can boot? I did not run exhaustive tests-can I run with this HDD without any issues?

Does anyone have experience with this?

Thanks in advance!

--Mark

Upgrading to 5,1 increases the CPU and RAM capacities (or speed). Check out House of Moth.

Your iMac can be restored to working order with a graphics card replacement, not a simple task, but doable. Or you can turn the iMac into an external display.

 

[Markintosh]

That’s good to know!

10.13 & my current hardware is actually fine for my use.

i just wanted to know if proceeding with my 10.13 HDD would work correctly, or will I experience erratic behavior and possible corruptions?