Universal Fixpack ships installFixPack (to install a fixpack),
but you have to install GA first.
Server Fixpack brings
db2setup - GUI Installer
db2_install - Console based Installation
installFixPack
So you can install directly from the server-fixpack and for universal-fixpack, you have to install a GA-Version first.
Elin asked, if the GA Version needs to be installed first. Since i always work with Universal-Fixpack, i was not aware that the server-fixpack brings an Installer to bypass the GA-Installation.
If there is a way to install (not upgrade) the software using installFixPack, i don't know it.