MP 1,1-5,1 Sequoia and Mojave on Same 5,1 Mac Pro?

[riven2000]

I'm running Sequoia 15.7.3 on a 5,1 cMP with OCLP, and am trying to find out how to run Mojave on the same machine for older software. It's installed now but won't boot. I'm a little fuzzy on this, but I think it has to do with OCLP not playing well with Mojave. Any way I can get both to run in this situation?

 

[Bigwaff]

Yes. Install Mojave on separate disk. Hold down Option key on boot to get Apple boot picker. Select Mojave disk.

 

[reader50]

I have every macOS installed on my cMP that it's capable of running: Snow Leopard through Sequoia. Tahoe will be added once OCLP supports it. Snow Leopard through Sierra have separate HFS+ partitions. Mojave through Sequoia share the same APFS partition. High Sierra has its own HFS+ partition on the SATA drive, but is in the shared APFS partition on the nVME drive.

Note: Leopard used to be bootable. I lost that capability after upgrading to X5680 CPUs. The Leopard kernel doesn't know what to do with this CPU family.

macOS versions that will boot through OCLP: Snow Leopard, High Sierra through Sequoia (and presently Tahoe).
macOS versions that will direct-boot: Snow Leopard through Big Sur.

notes: Catalina had to be installed with the DosDude install tool. Big Sur needs to be installed and patched via OCLP. But after that's all done, it will direct-boot.

Your copy of Mojave should boot through OCLP. Have you tried direct-booting (option key during boot)? If it won't boot either way, then try a reinstall while booted via OC. Or do that anyway, to cure the problem. Or use the DosDude install tool for Mojave while booted either way.

 

[riven2000]

Thanks all!! One thing I just remembered though - I'm using a Radeon RX 580 that doesn't have its own boot screen. Will this affect Mojave vs the OCLP boot screen? Haven't dealt with this in a while.

 

[reader50]

It will prevent you from using the firmware boot picker. It will be fine with the OCLP boot picker.

 

[riven2000]

Thanks again!

 

[Minghold]

Use an SSD. Format it APFS. Do NOT encrypt the drive. Install Mojave w/dosdude1 patcher (if necessary). Create another volume (not partition) with Disk Utility. Install Sequoia to an external via OP opencore, apply all updates, clone it to the 2nd volume with CCC6, reboot internal & apply OCLP rootpatches. Disable MDS_stores in Terminal in both OSes (you'll have to disable SIP both times).