Your are right, all works as before! Sorry for my confussion, but this is my first eReader.
I had already delate the books that come original from the device and all books I tried later had the same problem.
After you told me about the cause of the problem I reinstalled the original books and with them the font changing works fine as you said before.
I copy the content of the css files from one these books into one of my books and now I can change there fonts as well, but then missing the original font that is included in the epub. I try to create an css file that make both possible (internal and external fonts), but still with no success (css is also new topic for me). So situation is neither I have font change with all internal fonts or only have one external font. But I will look forward.
Thanks for your good hint!
