mksquashfs 4.5.1 (bookworm) writes a non-SQUASHFS_INVALID_BLK value for
xattr_id_table_start in the superblock even when -no-xattrs is passed, if
the source chroot contains POSIX ACL xattrs set by dpkg at install time.
Linux 6.1 squashfs driver then fails with "unable to read xattr id index
table" and refuses to mount the filesystem.
Strip all xattrs from the chroot via Python3 (already present) immediately
before mksquashfs runs. With an xattr-free source tree the resulting
squashfs is guaranteed to have SQUASHFS_INVALID_BLK in the xattr field.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
8d173175eb