I'm using Calibre under linux to convert my books and I'm getting mad about this LRF problem.
I have been having a look to https://www.mobileread.com/forums/showthread.php?t=25305
this threat but I guess that my problem is more document related than tool related.
Anyway, I attach my PDF (which is PRS-505 formatted, but I want to converto it to LRF).
Thanks to all in advance.