Le 24/03/2026 à 15:44, Haines Brown via Dng a écrit :
> Whats complicates things is that ext4 is a type of format and
> 0800 is a type of partition.

    Seems this is an sgdisk problem. I tried sgdisk and it warned me it
would convert my DOS partition table to GPT and I'd better quit before
any action.

    Other tools respect the partition table type you have on your disk.
For Linux, you have 83 for all Linux filesystems, 82 for swap and I
don't remember what for RAID and LVM. Then on 83, it is up to you to
create the filesystyem you prefer, ext4, btrfs or whatelse. I think
parted/gparted creates the filesystem for you and I guess sgdisk does
the same, hence the additional 2 digits.

    I suspect these additional two digits are a feature of GUID
partition tables. They don't exist on DOS partition tables and we have
lived and still live without them. I think Linux just ignores the
partition types; it is able to recognize which filesystem is on a
partition by reading its control block. I'd recommand to set the proper
two digits to the partitions as a hint anyway, and for sure if your disk
also hosts a Microsoft OS.

--     Didier