How to creae a pdf readable by Kindle 4

After some test I observed that Kindle 4 sometimes hangs reading PDF using a version greater than 1.4.

I suggest to use Ghostscript to convert the PDF document to the 1.4 version. The command is:

gs -dNOPAUSE -dBATCH -dFILTERVECTOR -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/ebook -sProcessColorModel=DeviceGray -sColorConversionStrategy=Gray -dOverrideICC -dCompressFonts=true -r150 -sOutputFile=/home/path/to/output.pdf /home/path/to/input.pdf