Mac OS + Windows + Linux Multiboot Tips

[vulgo]

What format do you use for you EFI partitions ?
3) is ext4 ; 4) is HFS ; 5) Is Swap ; but EFI1 and EFI2 ???

EFI partitions are formatted as certain FAT (MS-DOS) file systems. Use FAT32. Apart from being FAT, they have a special GPT GUID that identifies them as being EFI partitions (C12A7328-F81F-11D2-BA4B-00A0C93EC93B). This is not required by your firmware but operating systems may treat partitions differently with/without it so use partition type 'EFI System Partition' when creating these things.

- Linux will install it's bootloader - grub? - in EFI1 by default and we manually move it to EFI2
- MacOS will also install it's bootloader - clover? - in EFI1, and we let it there

macOS installs no bootloader. You install it manually with the Clover installer (and add an entry to the UEFI boot menu manually to complete the installation)

I want to do a clean install of MacOS
-the install process
- won't affect the partition 2)EFI2, 3)LinuxOs and 5)Linux Swap
- but it'll change 1)EFI1
- if for some reason I don't go all the way down and do not install clover on 1)EFI1, will I be able to boot in linux and how ?

macOS install process does not involve EFI partitions so won't affect any of them. Booting GRUB is handled by your firmware, GRUB is installed to an EFI partition and there is an entry in the UEFI boot menu pointing to its location (when you install GRUB the entry is created as part of the installation, unlike when you install Clover and you must add the entry yourself).

- I want to do a clean install of Linux
- the install process
- won't affect the partition 2)EFI2, 4)MacOs (and 5)Linux Swap)
- but it'll change 1)EFI1
- once I'm done I'll be able to boot in Linux from 1)EFI1, but not anymore on MacOS
- but if I want to boot in MacOS, I'll have
- to duplicate 1)EFI1 in 2)EFI2 and clear 1)EFI1
- boot with a my macos-install thumbdrive and install clover again, into 1)EFI1.

If as part of installing Linux you install GRUB, GRUB gets installed to a 'vendor' folder on an EFI partition. If you are installing e.g. the same distribution to the same EFI partition the same vendor folder will be used e.g. /EFI/UBUNTU, /EFI/FEDORA etc. other vendor folders e.g. EFI/MICROSOFT, EFI/CLOVER will not be touched. Other UEFI boot menu entries e.g. 'Microsoft Boot Manager', 'Clover' will not be touched. Depending on how GRUB is installed a new entry may be created in the UEFI boot menu or an existing one may be updated.

 

[Delphius]

Hi
thank's @Delphius, this is an awesome tutorial !

I have two question though.

First,
I got the idea that my had drive will have 5 partitions :
1)EFI1 2)EFI2 3)LinuxOS 4)MacOs 5)LinuxSwap

What format do you use for you EFI partitions ?
3) is ext4 ; 4) is HFS ; 5) Is Swap ; but EFI1 and EFI2 ???






Second,
Now if I'm right,
- Linux will install it's bootloader - grub? - in EFI1 by default and we manually move it to EFI2
- MacOS will also install it's bootloader - clover? - in EFI1, and we let it there

Now imagine I'm messing around a bit, and :
- I want to do a clean install of MacOS

-the install process

- won't affect the partition 2)EFI2, 3)LinuxOs and 5)Linux Swap
- but it'll change 1)EFI1

- if for some reason I don't go all the way down and do not install clover on 1)EFI1, will I be able to boot in linux and how ?​

- I want to do a clean install of Linux

- the install process

- won't affect the partition 2)EFI2, 4)MacOs (and 5)Linux Swap)
- but it'll change 1)EFI1

- once I'm done I'll be able to boot in Linux from 1)EFI1, but not anymore on MacOS
- but if I want to boot in MacOS, I'll have

- to duplicate 1)EFI1 in 2)EFI2 and clear 1)EFI1
- boot with a my macos-install thumbdrive and install clover again, into 1)EFI1.​

Am I right ?

Have I miss something ?

Thank's in advance for your reply

Regards

Trying to get caught up on this thread and think through these questions myself. It has been a while since I have gone through the process so Im having to remember all the tedious things that I figured out when I created this guide. Thanks to everyone who has also chimed to help out.

If I remember correctly, there were certain things that I was having issues with when installing the Linux side of things. I will go back through and try to remember which order or conflict I kept having. I just remember it was very difficult to have things playing nicely as things stacked up. However some of my experience and knowledge with EFI's might be limited. I remember when installing linux, no matter what I would choose for the grub installation location, it would seem to want to default to EFI 1 no matter what. Then I also remember having problems with the actually size of the EFI paritition, where Clover, grub, and Windows boot loaders wouldnt fit, or GRUB would crash during installation. I decided in the end to be on the safe side dozens of failed attempts or so. So I created all my EFI partitions manually, and made sure there was plenty of room to spare on each for flexibility. I think the default EFI size if things are done automatically is something like 128MB. So 512MB might be excessive, and two isolated partitions on the MacOS and Linux drive may be over kill or may have better ways of preventing this, but I just decided this would be a method that I could count on and was somewhat straight forward.

Hopefully that clears up a few questions as to some reasons. Feel free to shoot me more questions if more clarification is needed.