I'm not sure if you're being sarcastic, but there is!
I've jailbroken my Kindle Scribe and installed coreader and feed it my Calibre library and its awesome.
Oh and i kept it in airplane mode from the first day, which is important so it doesnt self update and break the jailbreak.
s/coreader/KOReader/g
Voice input or autocorrect?
a lack of concentration ;)
Kindles don't need to be jailbroken to transfer books via calibre (or a file manager or a terminal).