installing 10.12, 10.13 using HFS+ with an iMac Pro

[elitistjerk]

Has anyone had difficulties trying to install 10.12.x or 10.13.x on an iMac Pro with HFS+ partitions?

I have tried to use DosDude's patcher, but I get an extremely strange error when I'm in the installer, where selecting the disk says

“this operation cannot be completed (com.apple.osintall error -1)”

and then when I use an unpatched High Sierra installer, it says that this Mac only supports installation to APFS-formatted volumes, which I found very strange.

I couldn't even boot from the Sierra installer! it just would restart! this is insane! lol

 

[Nermal]

This post claims that a T2-based Mac can only boot from APFS. I haven't confirmed that, but I wouldn't be surprised if it's true.

As for installing 10.12, I wouldn't expect that to work at all, as 10.13 was current when the machine was released and earlier versions typically won't run.

 

[elitistjerk]

That's possible, but the macperformanceguide people seem to imply it was, at least at one point, capable of using HFS+:

2017 iMac Pro: APFS vs HFS SSD Speed

macperformanceguide.com

what they don't make clear on that graph, however, is if the SSD is the shipped AP2048 or simply testing an external SSD via Thunderbolt 3.

I didn't even realise this is the earliest T2 mac that was made :/ :/ Darn, looks like I have a situation on my hands. APFS feels so nasty. Its limitation with symbolic links has always stuck with me, even if that may not seem significant.

None of this explains why the Sierra USB doesn't even boot though, unless it was High Sierra where it was introduced as an (optional) choice.

 

[elitistjerk]

edit: I thought this would buy me a year or some change, but it really feels like I'm destined to be out of this ecosystem if restoring my Time Machine (HFS) backup via High Sierra USB boot fails.

Even if I get it working, what I found super weird was that after installing Mojave I couldn't even complete the "first start" prompts after putting in my iCloud. It would only let me click back, and not next.

Once I skipped iCloud credentials, it did let me proceed. Something feels so wrong with T2 macs, in general.

 

[elitistjerk]

My apologies! Apparently it was High Sierra that shipped in 2017, OWC (they are usually not wrong) https://eshop.macsales.com/guides/Mac_OS_X_Compatibility has an error.

It does look like I"ll be able to restore my HFS Mojave Time Machine backup via an unmodified High Sierra bootable USB. Since my backup drive is slow and old (4TB 5400 RPM lol), it's still sitting at the 'select a destination' screen.

Since the source backup is for a 2TB drive and I'm currently sitting at 1TB, I think I should be able to pick and choose what I want to restore?

If that works, I will be one very happy camper!

Edit: I cannot pick and choose what I would like to restore at this time I may have to return this because waiting for the AP2048 upgrade may be a risk I'm unwilling to take.

 

[elitistjerk]

Bregrudgingly using the Migration assistant to restore what I can, just to see if I will be happy with this thing.

Very nice piece of kit. I can't believe I got it for 900 CAD. Even with the cracked screen (top right), which has yet to catch my attention throughout usage today, this is one serious machine.

The 256GB RAM and 2TB upgrade I have coming, combined with this seemingly-exclusive-but-also-clever AliExpress knockoff of the Startech SATA dock (they added USB3 to the front, plus some card readers), costing me about another 600 or so CAD, makes this a serious steal even with that money put into it.

Don't even know if I could get the PC equivalent (even if I consider the used market) for the same amount.

 

[Significant1]

I don't understand why you want to use HFS+ as boot format. I also don't understand your reason to run 10.12 (not possible) or 10.13.

You can perfectly fine restore a Time Machine backup to a APFS machine, even if it originates from a HFS+ machine. You can also restore a backup made on a previous version of macOS to a newer version. Just use migration assistant.

I have myself just purchased a secondhand iMac Pro and it is running Sonoma fine. So I wouldn't mess with older macOS versions unless you have a reason.

Btw. the HFS+ test, you linked to, could be another partition on the built-in drive.

 

[elitistjerk]

I want HFS+ because i would like to keep my time machine backup history clean.

I don't want to backup to my existing time machine volume, only to learn that my most recent backup will not be used because it is HFS+ (in spite of the files being 99% the same). This would create an additional 2TB snapshot that is not necessary, even on a 12TB backup drive.

We will see if it's possible when I get my 2x1TB SSDs; hoping dosdude's patched high sierra installer wasn't teasing me!

Anyways, this thing is pretty awesome. I understand what Regulus was saying about it. It has a true 2191B as well, not some 2195 swapped in by a bum. So someone spent a serious amount of money on this machine and I know the insides have not been touched!

I would never even consider a 2019 Mac Pro after using this, because I get High Sierra and Mojave access ensuring older 32 bit Cocoa applications aren't thrown in the bin!

What a machine. Even at 6+ years old, these specs are impressive. At the time they were incredibly impressive. I just assumed it was a souped up Notebook spec, but was I ever wrong.

 

[chrfr]

I want HFS+ because i would like to keep my time machine backup history clean.

I don't want to backup to my existing time machine volume, only to learn that my most recent backup will not be used because it is HFS+ (in spite of the files being 99% the same). This would create an additional 2TB snapshot that is not necessary, even on a 12TB backup drive.

Time Machine backs up the files, not the file system. Converting your disk to APFS (which has a lot of advantages over HFS+ anyway) will not trigger a complete backup of all the existing files that have not changed.
Also, the iMac Pro first shipped with a custom build of 10.13.2. It will not boot Sierra, regardless of file system type.