Comment 0 for bug 2058826

Ubuntu iso images bundle the f2fs driver in initrd since 20.04, but casper does not recognize f2fs as a supported fs even in 24.04. Hence, the images cant loop-boot from f2fs partitions.

A 2-lines change is all that's required since 20.04 (casper-helpers since 22.04, previously this code was in lupin-helpers)

    --- casper-helpers
    +++ casper-helpers.new
    @@ -350,7 +350,7 @@
     is_supported_fs(){
         [ -z "${1}" ] && return 1
         case ${1} in
    - ext2|ext3|ext4|xfs|jfs|reiserfs|vfat|ntfs|iso9660|btrfs|udf)
    + ext2|ext3|ext4|xfs|jfs|f2fs|reiserfs|vfat|ntfs|iso9660|btrfs|udf)
                 return 0
                 ;;
         esac
    @@ -370,6 +370,7 @@
         modprobe reiserfs
         modprobe xfs
         modprobe jfs
    + modprobe f2fs
         modprobe vfat
         modprobe fuse
         [ "$quiet" != "y" ] && log_end_msg "...devs loaded..."

With some efforts (copy f2fs and crc32 modules from the squashed filesystem into the initrd) it works down to 18.04 live server and 15.10 desktop.

With such patch it works in 14.04.3 .. 14.04.6 desktop as well

    --- casper-helpers
    +++ casper-helpers.new
    @@ -46,7 +46,15 @@
             echo $FSTYPE
             return 0
         fi
    - /sbin/blkid -s TYPE -o value $1 2>/dev/null
    + /sbin/blkid -s TYPE -o value $1 2>/dev/null || {
    + # Check for f2fs
    + case "$(dd if="$1" skip=2 count=1 2>/dev/null)" in
    + "$(printf '\x10\x20\xf5\xf2')"*)
    + echo f2fs
    + return 0 ;;
    + esac
    + return 1
    + }
     }

     where_is_mounted() {

My script to apply the changes: https://github.com/slowpeek/ubuntu-remaster-f2fs