On 21/10/2024 at 10:26, Diederik de Haas wrote:
On Sun Oct 20, 2024 at 8:49 PM CEST, Pascal Hambourg wrote:
On 20/10/2024 at 16:28, Diederik de Haas wrote:
```
root@cs21:~# parted -s /dev/mmcblk1 print
Model: MMC NCard (sd/mmc)
Disk /dev/mmcblk1: 61.9GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 32.8kB 16.8MB 16.7MB primary
2 16.8MB 256MB 239MB fat16 primary boot, esp
3 256MB 61.9GB 61.6GB ext4 primary
root@cs21:~# lsblk -o +PARTFLAGS,FSTYPE /dev/mmcblk1
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS PARTFLAGS FSTYPE
mmcblk1 179:0 0 57.6G 0 disk
├─mmcblk1p1 179:1 0 16M 0 part
├─mmcblk1p2 179:2 0 228M 0 part /boot/efi vfat
└─mmcblk1p3 179:3 0 57.4G 0 part / ext4
```
Partition 2 looks like a regular EFI partition mounted on /boot/efi as
expected by GRUB. With a size of 239MB it should be FAT32 instead of
FAT16, but maybe the UEFI firmware expects only FAT16 or does not care.
I don't care enough (about FAT) to look into it, but I think 'vfat' can
mean either FAT16 or FAT32?
Yes, but some UEFI firmware are picky about the combinations of FAT type
and partition size they accept.
So it looks like it just needs some indication (flag) of what the boot
device is, but it doesn't (seem to) matter which one.
Weird. Does it have to be on the boot/root partition or can it be on any
other partition ?
It appears to not matter if it's 'boot' or 'legacy_boot', but it (ofc?)
needs to be set on the partition with the kernel as that needs to be
started for the rest of the boot process.
But in cs21's partition table, the boot/esp flag is on the EFI
partition, not the root partition. Does it mean that the kernel is
installed in the EFI partition instead of the root partition ? Or is the
"kernel" a secondary EFI boot loader such as GRUB ?
