Multibooting OS 10.10.5 & OS 10.13.02

[Dougal]

Hi, this is my first time posting on the forum; i hope it's in the right place.

I have a setup running Yosemete, installed using the unibeast guide and the posts on the forums. All of which were appreciated greatly, as i am not so technically minded.

I would not change it except for this whole spectre meltdown problem that affects intel CPU's, i have been advised to update to high seirra to protect against the issue. How can I do this in a way that won't bork Yosemete?

I have a free partition on my hdd, is it possible to create a fresh installation for hs using the same methods as before, and just boot into the new os partition from the bios, leaving Yosemete untouched, at least untill I can get everything working? Or would I need a new hard drive to install it onto alltogether?

The other problem is that my system definition is Mac Pro (Early 2008), from what i have seen this would not be a suitable system definition for High Sierra, can i use seperate definitions for the two different Mac OS's?

I see a lot of guides for multibooting between OSX + Win + Linux but not so many for 2 seperate versions of Mac OS, if anyone can point me in the direction of such a guide or just give me a few pointers it would be very much appreciated.

 

[Going Bald]

Hi, this is my first time posting on the forum; i hope it's in the right place.

I have a setup running Yosemete, installed using the unibeast guide and the posts on the forums. All of which were appreciated greatly, as i am not so technically minded.

I would not change it except for this whole spectre meltdown problem that affects intel CPU's, i have been advised to update to high seirra to protect against the issue. How can I do this in a way that won't bork Yosemete?

I have a free partition on my hdd, is it possible to create a fresh installation for hs using the same methods as before, and just boot into the new os partition from the bios, leaving Yosemete untouched, at least untill I can get everything working? Or would I need a new hard drive to install it onto alltogether?

The other problem is that my system definition is Mac Pro (Early 2008), from what i have seen this would not be a suitable system definition for High Sierra, can i use seperate definitions for the two different Mac OS's?

I see a lot of guides for multibooting between OSX + Win + Linux but not so many for 2 seperate versions of Mac OS, if anyone can point me in the direction of such a guide or just give me a few pointers it would be very much appreciated.

You most likely have 2 problems to overcome to be able to boot successfully both Yosemite and High Sierra.
One - you probably are using Chimera as your Yosemite boot loader. Chimera will not work with High Sierra - you must use Clover as your boot loader.
Two - in order to run High Sierra you must be using a system definition acceptable to HS. You may find an iMac is closer to your actual hardware then the MacPro definition.

A bit of research and experimentation may be of benefit to you. First, try to change over to Clover - you can create a test boot USB - https://www.tonymacx86.com/threads/test-drive-how-to-create-a-clover-usb.127134/ and try it out. Changing System Definitions with Clover Configurator is relatively easy as you can experiment without messing up your existing Yosemite drive's boot files.

 

[Dougal]

You most likely have 2 problems to overcome to be able to boot successfully both Yosemite and High Sierra.
One - you probably are using Chimera as your Yosemite boot loader. Chimera will not work with High Sierra - you must use Clover as your boot loader.
Two - in order to run High Sierra you must be using a system definition acceptable to HS. You may find an iMac is closer to your actual hardware then the MacPro definition.

A bit of research and experimentation may be of benefit to you. First, try to change over to Clover - you can create a test boot USB - https://www.tonymacx86.com/threads/test-drive-how-to-create-a-clover-usb.127134/ and try it out. Changing System Definitions with Clover Configurator is relatively easy as you can experiment without messing up your existing Yosemite drive's boot files.

Thanks for the suggestions, yes i am using Chimera as a boot loader. I did not know about being able to test boot with Clover so that is very helpful information, thankyou. Will be getting on with this over the next few days to see how it goes.