Lotus Domino/Notes 8.5.2 FP2 is available for download from FixCentral. I have already upgraded out test server on Linux and everything seems to be working so far.
Upgrading Lotus Notes Client 8.5.2 FP1 on Ubuntu 10.04 went wrong. Installer said something about missing /opt/ibm/lotus/notes/framework/rcp/deploy/jvm.properties.orig file and LN just did not start. After asking for password it's just showing the progress indicator that starts over and over....Removing Lotus Notes and Fixpack and installing it again solved it.
Meanwhile in the virtual machine not so far....
...install of FixPack 2 over LN8.5.2FP1 (notes/designer/admin win32) took longer time but works just fine.
EDIT: Since I blogged this I had another problem with FP2 installation on Ubuntu, this time on version 10.10. Installer complains about Fixpack having invalid string in revision number. Found solution in reply to this question