MP 1,1-5,1 Mojave (non Opencore) and Big Sur (OCLP) dual boot

[bobulusbillman]

Hi,

I have a 2012 Mac Pro 5.1 currently running a regular install of Mojave. An RX580 GPU. I've just bought a NVME drive (+PCI adapter) that I'd like to install Big Sur on using OCLP.

1. Once I've installed Big Sur, will it still be possible to boot back into my old install of Mojave? Like if I went into system prefs and selected the Mojave drive as the boot drive would that work?

2. If I run into problems during the Big Sur install, or if I simply decide not to use it after a few weeks, can I simply pull out the Big Sur drive out of the computer and it will then just revert back to booting into Mojave? Or does OCLP do an boot room tweaks.

Thanks so much. Opencore is an amazing piece of work!

 

[h9826790]

1. Once I've installed Big Sur, will it still be possible to boot back into my old install of Mojave? Like if I went into system prefs and selected the Mojave drive as the boot drive would that work?

Depends on your OpenCore config, I am not a OCLP user, can't tell. But most likely you can boot your existing Mojave via that OpenCore settings (regardless you want to load Mojave via OpenCore or not, once OpenCore is blessed, it should be the default boot loader, and it will load before Mojave by default).

If not, quite a few workaound exist. No need to worry about it.

2. If I run into problems during the Big Sur install, or if I simply decide not to use it after a few weeks, can I simply pull out the Big Sur drive out of the computer and it will then just revert back to booting into Mojave?

Can

Or does OCLP do an boot room tweaks.

It won't

 

[xuulan]

I have a very similar setup. I can say that you can NOT easily switch back and forth between Mojave and Big Sur (or Monterey). The latest version of OCLP lets you use GOP injection to get the OCLP boot screen selector, however even though the Mojave partition will shop up, it will give you the circle-slash when you try and boot from it. Since your RX580 will most likely not have been flashed, you won't be able to hold down option and boot Mojave and earlier, as well as legacy (non-EFI) Windows partitions. This is because Mojave and earlier, as well as legacy Windows requires the legacy boot picker, not the OCLP one.

To be honest the easiest solution is to pull the Big Sur/Monterey drive, reset the PRAM and then use the Startup Disk control panel if you need to boot Windows. To go back to Big Sur/Monterey, you'll have to use the command line to bless the OCLP EFI folder (which you would most likely have to do initially, anyway)

Tom

 

[h9826790]

This is because Mojave and earlier, as well as legacy Windows requires the legacy boot picker, not the OCLP one.

I don't think it's the boot picker's problem. Mojave also belongs to the EFI group, not legacy. However, the secure boot setting is different.

I believe OCLP use a more "big Sur specific" approach to install Big Sur for cMP. Which has the latest security features enabled. However, the downside is that the same setting (it's the OC setting, not the OC boot picker) not allow to boot previously installed Mojave.

There are few work around. The "more work but better result" solution should be re-install Mojave again via the same OCLP boot picker, just cover on top of the existing one should be good enough, no data lost. In this case, as long as the user don't perform NVRAM reset. The newly installed Mojave will still belongs to the same group, and able to boot with the same secure boot settings.

Another work around is just enable BootKicker in the OC boot picker. In this case, the user can select BootKicker, then the native Apple boot manager will show up, and the user can further select Mojave or even legacy Windows to boot.

A "more advance but higher risk" solution will be flashing the Mac to have native boot screen support for the non flashed RX580. So that it can provide native UEFI GOP boot screen for OP to hold option key to boot.

Or Simply use my OC package, which allow users to dual boot / install / update Mojave and Big Sur natively on cMP (because I use a different secure boot setting).

 

[equals]

I think the best way for a use case like yours is to use rEFInd (RefindPlus) + OpenCore chain-loading. You can achieve GOP boot screen via rEFInd (RefindPlus) and choose either to boot directly to Mojave or to run OpenCore instance which will load Big Sur. You may use MyBootMgr to set up your boot configuration or just do it yourself.

 

[xuulan]

I think the best way for a use case like yours is to use rEFInd (RefindPlus) + OpenCore chain-loading. You can achieve GOP boot screen via rEFInd (RefindPlus) and choose either to boot directly to Mojave or to run OpenCore instance which will load Big Sur. You may use MyBootMgr to set up your boot configuration or just do it yourself.

This did work for me, using OpenCore to launch rEFInd Plus. I couldn't get a boot screen with rEFInd Plus, but first booting into OpenCore with GOP injection enabled, then into rEFInd to boot either Mojave or Windows. It is a bit hit and miss, with two similar 5,1's, the rEFInd selection was available in OC and not in the other one.

 

[Heckmeck]

Hey!
Sorry I'm a bit confused on this topic.

I'm using a non flashed pc GPU in my MacPro 5.1 Mid2012.
I want to install Opencore Legacy but also want to boot my other internal volumes sometimes which have a natively supported OSX installed without Opencore.

@h9826790
How to activate OC Legacy Bootkicker? Wouldnt that be the easiest way to switch forth and back the volumes?
It's something different than Bootpicker i assume?

https://dortania.github.io/OpenCore-Legacy-Patcher/assets/img/OCLP-GUI-Settings-ShowPicker.5590d8b3.png

Or will i have to use refindPlus or always have to pull out my OC drive and do a nvram reset?

 

[h9826790]

Hey!
Sorry I'm a bit confused on this topic.

I'm using a non flashed pc GPU in my MacPro 5.1 Mid2012.
I want to install Opencore Legacy but also want to boot my other internal volumes sometimes which have a natively supported OSX installed without Opencore.

@h9826790
How to activate OC Legacy Bootkicker? Wouldnt that be the easiest way to switch forth and back the volumes?
It's something different than Bootpicker i assume?

https://dortania.github.io/OpenCore-Legacy-Patcher/assets/img/OCLP-GUI-Settings-ShowPicker.5590d8b3.png

Or will i have to use refindPlus or always have to pull out my OC drive and do a nvram reset?

There are basically three types of boot manager.

1) The native Apple boot manager (hold option key to boot). This required native boot screen support. Can’t use in blind. Otherwise, cMP hangs.

2) OpenCore boot picker. Can be used in blind. OpenCore also able to let cMP utilise the newer UEFI GOP to display boot screen. So that, as long as the graphic card isn’t too old. It’s possible to display boot screen on cMP without flashing.

3) OpenCore BootKicker. This is actually the native Apple boot manager. However, rather than hold option to boot. We call that out via OpenCore. And since OpenCore can activate UEFI GOP boot screen. Therefore, even the card isn’t flashed, it can still display the native Apple boot manager.

TBH, for today, it makes more sense to flash your cMP with EnableGop. So that you can simple hold Option key to boot. Even your graphic card isn’t flashed.

 

[Heckmeck]

@h9826790 heard about the option to flash your cMP with EnableGop. basically awesome but scary
So i'd prefer another solution atm.
If i got it right, oc boot picker wont let me switch to system that i didnt install via opencore, right?
So the only option will be bootkicker right?
How do i activate that?

 

[bladerunner88]

Hi,

I have a 2012 Mac Pro 5.1 currently running a regular install of Mojave. An RX580 GPU. I've just bought a NVME drive (+PCI adapter) that I'd like to install Big Sur on using OCLP.

1. Once I've installed Big Sur, will it still be possible to boot back into my old install of Mojave? Like if I went into system prefs and selected the Mojave drive as the boot drive would that work?

2. If I run into problems during the Big Sur install, or if I simply decide not to use it after a few weeks, can I simply pull out the Big Sur drive out of the computer and it will then just revert back to booting into Mojave? Or does OCLP do an boot room tweaks.

Thanks so much. Opencore is an amazing piece of work!this on a Mac pro (6.1)

I have done this on a Mac Pro (6.1) without the open core part. I can't select the Big Sur Patition in Startup Disk Mojave so have to restart holding down the Option Key to boot into Big sur. However when am in Bug Sur Mojave does show up in Startup Disk and am able to Boot back into Mojave normally.

 

[Heckmeck]

I have done this on a Mac Pro (6.1) without the open core part. I can't select the Big Sur Patition in Startup Disk Mojave so have to restart holding down the Option Key to boot into Big sur. However when am in Bug Sur Mojave does show up in Startup Disk and am able to Boot back into Mojave normally.

yes that's normal not to see big sur in startup disk using mojave. I boot Catalina in between, because there it works. Using Catalina or higher os you can see all os disks in system settings startup disk.

 

[h9826790]

If i got it right, oc boot picker wont let me switch to system that i didnt install via opencore, right?

It can, as long as the system belongs to EFI. In fact, at the very beginning, we simply install OpenCore after native Mojave installed. And simply use that to activate HWAccel.

How do i activate that?

At the Tools section

<key>Tools</key>
        <array>
            <dict>
                <key>Arguments</key>
                <string></string>
                <key>Auxiliary</key>
                <true/>
                <key>Comment</key>
                <string></string>
                <key>Enabled</key>
                <true/>
                <key>Flavour</key>
                <string>Auto</string>
                <key>FullNvramAccess</key>
                <true/>
                <key>Name</key>
                <string>BootKicker</string>
                <key>Path</key>
                <string>BootKicker.efi</string>
                <key>RealPath</key>
                <false/>
                <key>TextMode</key>
                <false/>
            </dict>
        </array>

 

[Heckmeck]

It can, as long as the system belongs to EFI. In fact, at the very beginning, we simply install OpenCore after native Mojave installed. And simply use that to activate HWAccel.

i dont get that part. You mean if i install mojave via opencore? And why would i activate HWaccel? I dont know what that is actually

Thanks for Bootkicker activation info! I now activated it and i could boot my natively installed non-opencore high sierra volume.
BUT when i tried to boot the opencore legacy monterey volume again it said: This version of mac os is not supported. From there on i couldnt boot any Mac OS anymore until i did nvram reset. Always same error message and slashed circle.
Can i somehow revive the opencore monterey volume? Anytime i bless it i get the oc bootpicker back but when i boot anything it says: version not supported.
And did i get it right that i can use Bootkicker to switch forth and back between booting natively supported non-opencore volumes and opencore volumes?
If so i wonder what i did wrong.

 

[h9826790]

i dont get that part. You mean if i install mojave via opencore? And why would i activate HWaccel? I dont know what that is actually

Thanks for Bootkicker activation info! I now activated it and i could boot my natively installed non-opencore high sierra volume.
BUT when i tried to boot the opencore legacy monterey volume again it said: This version of mac os is not supported. From there on i couldnt boot any Mac OS anymore until i did nvram reset. Always same error message and slashed circle.
Can i somehow revive the opencore monterey volume? Anytime i bless it i get the oc bootpicker back but when i boot anything it says: version not supported.
And did i get it right that i can use Bootkicker to switch forth and back between booting natively supported non-opencore volumes and opencore volumes?
If so i wonder what i did wrong.

OpenCore is just a boot loader. We can use it to bride boot some other OS (e.g. macOS).

The macOS is installed via OpenCore or not doesn't really matter.

We can install OpenCore, then install macOS via OpenCore. Or install macOS natively, then install OpenCore. Both ways work.

HWAccel is a GPU function to provide high performance H264 / HEVC videos decoding / encoding. If you don't need it, you don't need to activate it.

I never use OCLP, not quite sure how it config. But in general, if you want to boot Mojave or earlier OS. You don't need OpenCore. If OpenCore boot picker allow you to boot to Mojave / High Sierra, then it's find.

But if you can't boot to those natively supported OS via OpenCore, then it means OpenCore is specifically configured to boot to some newer OS. In that case, you can boot to those OS via Boot Kicker.

But then when you want to boot Monterey, you must first boot back to the OpenCore boot picker, and select Monterey from there. Otherwise, your cMP will try to boot Monterey natively. Then of course it won't work.

If you often need to switch between some natively installed old macOS, and OCLP Monterey. May be you should check out RefindPlus. That may make your life easier.

 

[Macsonic]

I'm using either OpenCore Legacy Patcher or Martin Lo's Opencore. So far I'm able to boot into Mojave, High Sierra in OpenCore Legacy Patcher or in Martin Lo's Opencore with Big Sur, Catalina or Monterey. Both OCLP and MLo's Opencore are excellent programs.

And can also boot into the Apple Legacy Bootscreen (with white screen and HD icons) holding down the Option key. I'm using a flashed Nvidia 680 or Quadro K5000 with boot screens.

Installing Mojave under Opencore is possible or as a stand-alone native installer is fine.

 

[h9826790]

Flash the cMP with EnableGop to allow RX580's native boot screen (allow hold Option key to boot) may be the easiest way to boot different OS in his case indeed.

 

[Doc2005]

I don't think it's the boot picker's problem. Mojave also belongs to the EFI group, not legacy. However, the secure boot setting is different.

I believe OCLP use a more "big Sur specific" approach to install Big Sur for cMP. Which has the latest security features enabled. However, the downside is that the same setting (it's the OC setting, not the OC boot picker) not allow to boot previously installed Mojave.

There are few work around. The "more work but better result" solution should be re-install Mojave again via the same OCLP boot picker, just cover on top of the existing one should be good enough, no data lost. In this case, as long as the user don't perform NVRAM reset. The newly installed Mojave will still belongs to the same group, and able to boot with the same secure boot settings.

Another work around is just enable BootKicker in the OC boot picker. In this case, the user can select BootKicker, then the native Apple boot manager will show up, and the user can further select Mojave or even legacy Windows to boot.

A "more advance but higher risk" solution will be flashing the Mac to have native boot screen support for the non flashed RX580. So that it can provide native UEFI GOP boot screen for OP to hold option key to boot.

Or Simply use my OC package, which allow users to dual boot / install / update Mojave and Big Sur natively on cMP (because I use a different secure boot setting).

Hi, method 2 sounds very interesting for me. Can you please explain exactly, how you enable the Bootkicker in the OC boot picker? Thanx!

 

[Doc2005]

There are basically three types of boot manager.

1) The native Apple boot manager (hold option key to boot). This required native boot screen support. Can’t use in blind. Otherwise, cMP hangs.

2) OpenCore boot picker. Can be used in blind. OpenCore also able to let cMP utilise the newer UEFI GOP to display boot screen. So that, as long as the graphic card isn’t too old. It’s possible to display boot screen on cMP without flashing.

3) OpenCore BootKicker. This is actually the native Apple boot manager. However, rather than hold option to boot. We call that out via OpenCore. And since OpenCore can activate UEFI GOP boot screen. Therefore, even the card isn’t flashed, it can still display the native Apple boot manager.

TBH, for today, it makes more sense to flash your cMP with EnableGop. So that you can simple hold Option key to boot. Even your graphic card isn’t flashed.

 

[Doc2005]

Can you please explain Method 3? Ho can I activate BootKicker? Thanx

 

[h9826790]

Can you please explain Method 3? Ho can I activate BootKicker? Thanx

Make BootKicker avail under the Tools section

<key>Tools</key>
        <array>
            <dict>
                <key>Arguments</key>
                <string></string>
                <key>Auxiliary</key>
                <true/>
                <key>Comment</key>
                <string></string>
                <key>Enabled</key>
                <true/>
                <key>Flavour</key>
                <string>Auto</string>
                <key>FullNvramAccess</key>
                <true/>
                <key>Name</key>
                <string>BootKicker</string>
                <key>Path</key>
                <string>BootKicker.efi</string>
                <key>RealPath</key>
                <false/>
                <key>TextMode</key>
                <false/>
            </dict>
        </array>

 

[lrclfelsrs]

1st post here. Many thanks to the MacRumors community.

I also am attempting dual boot on my 5,1 cMP. I have Mojave installed on a PCIe SSD. I partitioned the SSD and successfully clean installed Monterey 12.6.8 using OCLP 0.6.8 on the second partition. After reading this thread, it is no surprise that I get the slashed circle when attempting to boot Mojave.

There are few work around. The "more work but better result" solution should be re-install Mojave again via the same OCLP boot picker, just cover on top of the existing one should be good enough, no data lost. In this case, as long as the user don't perform NVRAM reset.

Of all the methods presented here, this one seems the most intuitive to me and the one I will attempt. I already have a USB Mojave installer and backed up my Mojave partition. But has anyone ever tried just reinstalling Mojave using OCLP bootpicker? Any tips? More work? Am I missing something?

Are there any any good tutorials for bootkicker or rEFIndPlus? I've only done preliminary research on these, seems much more required.

 

[lrclfelsrs]

Update: got nowhere with trying to reinstall Mojave when attempting to launch installer with OCLP bootpicker. I just got the slashed circle again.

 

[sfalatko]

Your problem with Mojave is most likely that your OC install is spoofing a MacPro7,1 which does not support Mojave. You can add a no compatibility check (-no_compat_check is the syntax) boot argument to your config.plist.

 

[lrclfelsrs]

Your problem with Mojave is most likely that your OC install is spoofing a MacPro7,1 which does not support Mojave. You can add a no compatibility check (-no_compat_check is the syntax) boot argument to your config.plist.

Thanks, sfalatko, I'll give that a try.

 

[Foo_Fighter]

Hello everyone! I have a dual processor Mac Pro 5,1 currently running Mojave on a NVME drive (+PCI adapter) on slot 4, GPU's a Radeon Vega 64 and I also have a legacy BIOS Windows 10 installed on separate SSD. It's been running great for years. I recenty flashed cMP's firmware with EnableGOP an after so many years I can finally have the native boot picker. Thanks a lot for that! That made me want ro try to update to Monterey. Just like OP mentioned, I want to switch back and forth from my native non opencore Mojave install and Monterey through opencore. This is my working computer and there's a couple of old plugins that I'm not 100% sure they are supported on Monterey, so I want to test it for, let's say a couple of months, to make sure that all my needed software and plugins will work.

I bought a new CRUCIAL MX500 SSD for Monterey and used Martin LO's opencore 0.9.8 installed on a usb thumbdrive's EFI folder. I could boot into opencore with it's bootpicker, booted into Mojave from there, and properly installed Monterey on the new SSD. Everything seemed alright. I played around for a while, installed a couple of things, rebooted once to make sure that I could properly reboot into Monterey and called it a day.

The next morning I booted into my native Mojave install with native boot picker and worked for the rest of the day. The problem now is that I can't boot again to Monterey through opencore bootpicker. I can select it, see the loading bar stop at like 2% and then computer will reboot... I'm not sure what I did wrong. Apparently this is something that could be done, isn't it?

I would really appreciate if someone could tell me how I could get back to Monterey or how I should properly install it, if I did it wrong. Thank you very much!