Re: Debian 12 installation - installation USB stick boots to grub prompt

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

Chris Green wrote:
> > (proc) (memdisk) (lvm/q957--vg-swap_1) (lvm/q957--vg-root)  (hd0)
> > (hd0,apple2) (hd0,apple1) (hd0,msdos2) (hd1) (hd1,gpt1) (hd2)
> > (hd2,msdos5) (hd2,msdos1)

David Wright wrote:
> So hd0 is the USB stick.

Looks like that. Apple Partition Map is not much in use on amd64 disks.


> I'm guessing appleX gives you a UEFI view, and msdos2 an MBR view.

If this is something like debian-12.7.0-amd64-netinst.iso , then
(hd0,apple1) is possibly the non-mountable overall Apple Partition Map
range entry.

(hd0,apple2) and (hd0,msdos2) would both point to the ISO's EFI
System Partition. Quite small: 9.5 MB.

(hd0) would be the ISO 9660 filesystem.
This is what i expect Linux to need as root filesystem.

-----------------------------------------------------------------------
Technical note:

David Wright wrote:
> The reason I used apple2 is because viewing
>   gdisk debian-12.7.0-amd64-netinst.iso
> as a GPT partition table gives a listing with only partition 2.

debian-12.7.0-amd64-netinst.iso has three partition tables:

- A valid MBR ("msdos") partition table with unusual layout.
  Partition 1 begins at LBA 0 and encloses partition 2.
  (GRUB does not believe in such a partition and thus shows only
   MBR partition 2 as (hd0,msdos2).)
  Partition 2 marks the EFI boot image. This boot image serves as
  EFI System Partition when booting starts from an USB stick.

- A valid Apple Partition Map which quite uselessly marks the EFI
  boot image, too. EFI does not look at Apple partition maps.
  (Historically it stems from a small HFS+ filesystem image, which
   helpded Fedora ISOs to boot some pre-EFI Macs.)

- An invalid GPT, not announced by the MBR partition table.
  Some older EFI firmwares do not consider a device for booting if it
  does not have a GPT header block.


Have a nice day :)

Thomas