mount -t squashfs /home/hartmut/test/puppy-4.2.1-MULTIUSER-r3/pup_421.sfs /mnt
mount: wrong fs type, bad option, bad superblock on /dev/loop0,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so
Feb 6 20:46:14 Jupiter kernel: [22568.657821] SQUASHFS error: Major/Minor mismatch, older Squashfs 3.1 filesystems are unsupported
Feb 6 20:46:14 Jupiter dbus-daemon[861]: **** TREATING CHANGE AS ADD /sys/devices/virtual/block/loop0
Feb 6 20:46:14 Jupiter dbus-daemon[861]: **** ADDING /sys/devices/virtual/block/loop0
Feb 6 20:46:14 Jupiter dbus-daemon[861]: **** UPDATING /sys/devices/virtual/block/loop0
Feb 6 20:46:14 Jupiter dbus-daemon[861]: **** IGNORING ADD /sys/devices/virtual/block/loop0
Feb 6 20:46:14 Jupiter dbus-daemon[861]: **** TREATING CHANGE AS ADD /sys/devices/virtual/block/loop0
Feb 6 20:46:14 Jupiter dbus-daemon[861]: **** ADDING /sys/devices/virtual/block/loop0
Feb 6 20:46:14 Jupiter dbus-daemon[861]: **** UPDATING /sys/devices/virtual/block/loop0
Feb 6 20:46:14 Jupiter dbus-daemon[861]: **** IGNORING ADD /sys/devices/virtual/block/loop0