I just now upgraded to 4.2f22 and browsing from the ebook works now
So the solution for the 1200 is to upgrade to 4.2f22. For the 1150, I don't know what is the minimum firmware version required (or if it is OK for everyone).
There were a lot of fixes mentioned before I was able to upgrade, so I'd recommend everyone to upgrade anyway (Thanks to Garth at eBook Technologies, who arranged the upgrade within hours of me sending a mail).