I give up ... finding my answer with googling. Here is my question:
I have a prs-900 which more and more frequently shows question marks instead of letters. On googling and further investigation I found that the native font just does not have the required glyphs.
The only solution I found here all involve CSSs and Calibre, but I do not want to modify the ePubs with Calibre or any other program.
What I am looking for is either to install a different, more inclusive, fonts or use a different, more inclusive, font and rename it to the native font name.
Can it be done? Has it been done? If so where is it descibed?
Any help would be very much appreciated.