Problem:
UCC images may be to small for some needs. They may be grown by building a complete own image (like described in Generation of adapted UCC images) but this will need some time and effort.
Solution:
The existing image (with ext3 or ext4 filesystem) can simply be grown to the desired size by using the tools truncate and resize2fs. To grow the image (usually found in /var/lib/univention-client-boot/) by one gigabyte, the following commands may be used:
truncate -s +1G <image file name>
fsck.ext4 -f <image file name> # fsck.ext3 respectively
resize2fs <image file name>