Bug#1099700: Bug#1121934: cdrom: Target install partition fails to mount in EFI installer. Works in non-EFI installer
Adding two related unanswered bug reports to the Cc: list.
On 05/12/2025 at 22:35, Pascal Hambourg wrote:
On 05/12/2025 at 22:02, daan.nusman wrote:
* Installed Debian 13.2 with LVM/crypt + not a full random overwrite
(canceled it): the reported mount fail error occurred here. Suspected
the cancel was to blame, so:
This created an EFI partition as #1, with maximum size 1GB. The
installer tries hard (maybe too hard ?) to not reformat EFI partitions,
so if it detects any filesystem in it, then it won't reformat it but
will try to mount it as vfat in any case regardless of the detected
filesystem type.
If the former /boot partition and the new EFI partition had the exact
same position and size, then the installer detected the old ext4
filesystem and did not reformat the partition as FAT. Then it tried and
failed to mount it as vfat.
This may happen with guided partitioning using an entire disk or manual
partitioning after deleting the existing partition or creating a new
partition table. I suspect it happens because partman-partitioning does
not properly clean partman device directory during these operations.
Other use cases are in manual partitioning or guided partitioning using
free space when re-using an existing partition, either non-EFI or EFI
with a filesystem other than FAT, as EFI.
To summarize the troublesome use cases:
* manual partitioning
- re-use an existing EFI partition containing a non-FAT filesystem
- re-use an existing non-EFI partition as EFI
- delete an existing partition and create an EFI partition at the same
location
- create a new partition table and an EFI partition at the same location
as an old partition
* guided partitioning using free space
- re-use an existing EFI partition containing a non-FAT filesystem
* guided partitioning using an entire disk
- create a new partition table and an EFI partition at the same location
as an old partition
Cleaning partman device directory when creating a new partition table or
deleting a partition would not fix the partition re-use use cases.
Should we enforce that an EFI partition must have a FAT filesystem ?
It has been reported that some UEFI firmware may support other
filesystems such as exFAT or NTFS.
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