@diba: Use KindleTool
. (It's the -t flag). (And a convert -i will tell you the target OTA level of the official update, which is 1725970040 for 3.4)
Note that Sir Alex used official-OTA-level + 1 as the target level of his packages.
(That was the only extent of Sir Alex's changes to the python packer: some tweak for his OpenSSL setup, and a different hardcoded target OTA level, so, it should be pretty easy to move the build scripts to KindleTool. Check any of my K2/K3 hacks if you're confused, the build-scripts supports both the python tool & KindleTool).