Originally Posted by kartu
I am confused. So with this hack epubs won't work untill you create your css file, or did you mean "any change"?
Oh dear, sorry if I confused you. To be more specific, the hack process does not create the /epub/userStyle.css file. However, I believe the 505 will continue to display epubs using its original epub default fonts until you manually create the /epub/userStyle.css file which should point at your new preferred fonts already contained in the /fonts directory.
Any epubs which have their own customised fonts (either embedded or specified using extra-CSS during Calibre conversion) should use these book-specific fonts no matter what is in userStyle.css or even if userStyle.css doesn't exist.
I hope this is clearer. If I've got anything wrong please correct me, pepak.