If you check the "similar threads" below your post it appears that there are some suggestions however am not sure if any worked. The following link is an example
https://www.mobileread.com/forums/sh...d.php?t=280895
You might also try posting your question in the "Sony Reader Dev Corner" since one the suggestions is to try to "Flash the Firmware". . . not sure what that is all about but it sounds interesting.