Let's make this first post easy to read:
So, is the Kindle 4 jailbroken?
Not officially, but you can SSH into the device in diagnostics mode:
https://www.mobileread.com/forums/sho...&postcount=202
How about the Kindle Touch?
Yes.
https://www.mobileread.com/forums/sho...d.php?t=160454
Kindle Fire?
That's a completely different system and I do not care about it.
What has been done?
-Dump the Kindle 4 rootfs (and serial connection is working)
-Dump the Kindle Touch rootfs (thanks hondamarlboro and ramirami)
-Bootloader access:
https://www.mobileread.com/forums/sho...&postcount=196
-Only Kindle 4s can SSH and usbnetwork:
https://www.mobileread.com/forums/sho...&postcount=202
What needs to be done?
-Rewrite the kindle update tool to generate Touch/4 compatible updates
-Find a vulnerability for the Kindle 4
-Write some hacks for Kindle Touch
What can I do to help?
-If you are a developer/hacker, join our conversation in this thread or the IRC channel. We are looking for experts in ARM assembly and shellcode writing (in ARM) but all are welcome.
-If you have a broken Kindle 4 or Kindle Touch (or any other device), consider donating it for testing.
-If you are a Java developer and are interested in writing reader plugins and reader extensions (epub reader anyone) and wants help getting started, contact me
IRC Channel?
I'm glad you asked, we now have an IRC Channel.
irc://irc.freenode.net:6667/kindledev