I have an old Macbook pro (so EFI boot) which I dual boot.
More specifically it has two SSD drives in it.
The normal drive bay contains an SSD with Mac OSX installed on it, and nothing more, and the normal OSX boot loader.
I replaced the broken DVD with a an adapter that allows me to put a second SSD where the DVD used to be.
To install OSX I would unscrew the backplate and disconnect the drive cable to the DVD bay, so now Debian is safe from the OSX installer.
To install Debian I disconnect the normal drive and so OSX is safe from the Debian installer. I do this because this is a development machine and so I am always messing about with one OS or another.
I suppose that this means that there are two different efi partitions on two separate drives.
To select which OS to boot I press the power button and when the Macbook chimes I press the "option" key and the Macbook boot menu appears with a choice of the two drives.
If I select the left one Mac OSX boots.
If I select the right one grub on the Debian drive boots.
Initially I just get the grub command prompt (not the grub-rescue prompt).
If at that point I type "reboot" then the macbook reboots and if I don't press the option key then this time I will get the grub menu and can boot Debian from the menu.
The next thing I noticed is that after pressing the option key and selecting the Debian drive, from the grub prompt if I type "ls" then I can find my Debian ext partition, it comes up as (hd5,gpt2)
I also notice that after doing the reboot thing that once the menu comes up if I press "e" for edit that seems to be trying (hd1,gpt2).
So then I had a look at /boot/grub/grub.cfg
Code: Select all
insmod ext2
set root='hd1,gpt2'
also I cannot figure out how hd1 gets there, or how to change it to hd5
I had a look at all of the files in /etc/grub.d but it's just too complicated for me to figure out.
Can anyone tell me what's going on and how I can change my set root from hd1 to hd5 ?
All of the files in /etc/grub.d are default except that they are some extra lines under linux_gfx_mode in 10_linux to disable the GPU.
The debian drive was created from a clean install of Buster.
thanks, DNJ