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Bug#1078871: some more data for bug



For that first 16MB partition it would be nice to use GPT type EF02
(BIOS boot partition) so partitioning tools will see that it is
partition for bootloaders.

I created test 512MB disk and created some partitions by hand:

gdisk:
Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048           34815   16.0 MiB    EF02  BIOS boot partition
   2           34816          165887   64.0 MiB    EF00  EFI system partition
   3          165888          690175   256.0 MiB   8300  Linux filesystem
   4          690176          915455   110.0 MiB   8E00  Linux LVM

parted:
Number  Start   End     Size    File system  Name                  Flags
 1      1049kB  17.8MB  16.8MB               BIOS boot partition   bios_grub
 2      17.8MB  84.9MB  67.1MB               EFI system partition  boot, esp
 3      84.9MB  353MB   268MB                Linux filesystem
 4      353MB   469MB   115MB                Linux LVM             lvm

Parted is a tool from MBR era and it's support GPT is poor that's why
it has 'Flags' column with 'what parted thinks it is'.


This way part1/ef02 is not formatted, part2/ef00 is vfat (never
mind which variant) and rest of partitions are formatted to whatever
filesystem OS wants.

Separate /boot/ is handy if user wants to have / on LVM (crypted or
not) as this allows 'OS loader' (grub-efi in Debian) to load kernel,
initramfs (and dtb if needed) from /boot and start the OS.


And for our sanity we pretend that whatever firmware system is using
(edk2, u-boot, barebox, etc.) it knows how to load 'OS loader' EFI
binary from EF00 partition. For Debian it means grub2-efi.

If hardware does not handle EFI variables (so we can not store
BootOrder vars) then /efi/boot/bootaa64.efi should be written as this
is default name for OS loader in EFI/aarch64 world.


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