GNU bug report logs - #66448
[PATCH] image: Add 'lba partition label.

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Message #14 received at 66448 <at> debbugs.gnu.org (full text, mbox):

From: Mathieu Othacehe <othacehe <at> gnu.org>
To: Gabriel Wicki <gabriel <at> erlikon.ch>
Cc: 66448 <at> debbugs.gnu.org
Subject: Re: bug#66448: [PATCH] image: Add 'lba partition label.
Date: Fri, 13 Oct 2023 15:02:25 +0200

Hello,

> I didn't follow the whole source tree to figure out how all of this
> works, but this tiny change makes the image partition show up as LBA.

I had a closer look, this flag has no effect at all. If the 'esp flag is
set then the MBR partition type is set to 0xEF (EFI partition). If the
flag is removed, then depending on the file-system type: "fat16"
or "fat32", the partition type will be 0x0E or 0x0C which are
respectively FAT16 with LBA an FAT32 with LBA.

I guess that by removing the 'esp flag and adding the 'lba flag you
ended up with an LBA partition. That was the consequence of removing the
'esp flag, not adding the 'lba flag.

The partition type is specified in the partition->dos-type procedure of
(gnu system image). The corresponding types can be found here:
https://en.wikipedia.org/wiki/Partition_type.

We could improve the documentation here by stating that fat16 and fat32
partitions are by default LBA compatible, but the source modification in
not needed.

Thanks,

Mathieu

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