Michael wrote: > On Sunday, 28 April 2024 19:39:16 BST Dale wrote: >> Grant Edwards wrote: >>> On 2024-04-28, Grant Edwards <grant.b.edwa...@gmail.com> wrote: >>>> With DOS disk lables, Grub uses empty space between the boot sector >>>> and the first partition as a location to store it's core image file. >>>> That empty space does not exist when using GPT disk label. When using >>>> a GPT disk label, Grub requires that you need to create a "BIOS Boot" >>>> or "Grub Boot" partition so that Grub has somwhere to store it's core >>>> image[1]. >>> And it bears repeating that the bios/grub boot partition only needs to >>> be 1 or 2MB in size, is _not_ formatted with a filesystem, and is >>> _not_ the same as either >>> >>> 1) The "boot" directory where the kernel images and grubs other files >>> >>> are installed within a Linux filesystem. [Which you still need >>> when booting in Legacy/BIOS mode.] >>> >>> or >>> >>> 2) The UEFI partition that's formated with a FAT filesystem and used >>> >>> in UEFI boot mode [which you don't need when booting in >>> Legacy/BIOS mode.] >> I think I got a grasp on this now. Basically, partitions should be like >> this. >> >> >> First spot is the alignment thing. Usually a few MBs or so and unused. > This is created automatically by the partitioning tool, in your case cgdisk, > when you create the first partition on the disk and accept the default > starting sector. > > >> Grub boot partition with ef02 setting, not to be formatted. >> >> /boot partition for kernel and init thingy. Usually 1GB or so, enough >> for memtest, bootable rescue image etc. >> >> / or root partition that is around 150GBs or so. Enough to expand a bit >> and includes /usr and /var. >> >> /home rest of disk unless some needed for something else. >> >> >> Do you recall when running grub-install what that command looks like? >> Lets say the Grub partition with ef02 setting is sda1, would it be >> grub-install /dev/sda1 or just sda and it finds the empty partition on >> its own? > The unformatted and empty /dev/sda1 'BIOS Boot Partition' will be found by > GRUB when you run grub-install and it will store its core.img in there. > > You install GRUB's boot.img in the MBR and therefore you have to specify the > disk, NOT a partition, e.g.: > > grub-install /dev/sda > > This command should: > > 1. Install GRUB's boot.img in the MBR of /dev/sda. > 2. Install GRUB's core.img in /dev/sda1 which you created as a 'BIOS boot > partition', type EF02. > 3. Create directory /boot/grub to install all the grub fs drivers and files. > > If you have mounted /boot, all is well. If you are repairing an installation > from a liveUSB you can mount the /boot partition, e.g. /mnt/gentoo/boot and > specify this in the CLI: > > grub-install --boot-directory=/mnt/gentoo/boot /dev/sda > > NOTE: As per the link Grant helpfully posted you can create the 'BIOS boot > partition' with cgdisk "... by setting the partition type to 0xEF02 and > giving > it a label of gptbios". > > https://wiki.gentoo.org/wiki/GRUB#BIOS_with_GPT >
That's what I was thinking. I think I got it. I need to make notes of this tho. Before I forget. :/ Thanks to all. Dale :-) :-)
