have you tried with a hard drive installed there's not a great deal of storage space on the prismcube without a hdd
BlackHole 1.2.2
elmo login: root
root@elmo:~# df -h
Filesystem Size Used Available Use% Mounted on
ubi0:rootfs 308.1M 160.9M 147.2M 52% /
devtmpfs 157.9M 0 157.9M 0% /dev
tmpfs 157.9M 0 157.9M 0% /dev/shm
tmpfs 157.9M 280.0K 157.7M 0% /run
tmpfs 157.9M 0 157.9M 0% /sys/fs/cgroup
tmpfs 157.9M 32.0K 157.9M 0% /tmp
tmpfs 157.9M 120.0K 157.8M 0% /mtmp
/dev/ubi1_0 15.3M 112.0K 15.2M 1% /config
/dev/sda2 9.8G 150.7M 9.2G 2% /mnt/hdd0/pvr
/dev/sda3 9.8G 1.5G 7.9G 16% /mnt/hdd0/program
/dev/sda5 98.4G 187.8M 93.3G 0% /mnt/hdd0/media
root@elmo:~#