Analyzing Kindle 4.0

Well, Amazon might as well have stolen my wallet, because I am going to lose a couple hundreds of dollars. However, what fun is a Kindle if we can’t run our own code? (Answer: still pretty fun, but that’s besides the point.) Anyways, I haven’t gotten my hands on the new Kindles yet, but I got the next best thing: a software update from Amazon (

If you want to follow me and others try to crack this thing, visit this thread on MobileRead.

I’ll post some of the more important stuff we find on this post, so check back regularly.

  • The update format has changed! No more signatures for each file in the update, the update itself is signed and will refuse to extract unless the signature check passes. That means no more easy way out. To get “” to recognize and extract the new update, remove the signature (first 0x140 bytes) and change “FC04” to “FC02” (Bytes 0x0 to 0x4 after trimming the signature header). Now delete 4 bytes starting from 0x8 and 6 bytes starting from 0x10. (Offsets depend on the SP01 part removed). Now “” will recognize it.

  • Kindle 4.0 is codenamed “Yoshi” following “Luigi” (3.0) and “Mario” (2.0) (I can’t remember 1.0). It is built for the iMX50 (800MHz ARM Cortex A8) platform. The Kindle 3 is iMX35 (532MHz ARM) and the Kindle 2/DX is iMX3 (400MHz ARM).


  1. Serge A. Levin

    Also managed to unpack the update :) Looks like diff-patching is not the only available but the default used way to install the updates.

  2. Aqqa

    Hopefully we’ll be able to run it on 3.0. As we did on 2.0 to 3.0. It was like 33 in a difference or so..

    Sorry for my bad english. ;)

  3. Serge A. Levin

    3.3 otaup script looks a little bit changed against 3.2.1. But seems to be wrong point of counter-attack

  4. Hi there! I know this is sort of off-topic however I had to ask. Does operating a well-established blog like yours require a lot of work? I’m brand new to operating a blog however I do write in my journal on a daily basis. I’d like to start a blog so I can easily share my own experience and thoughts online. Please let me know if you have any kind of ideas or tips for new aspiring bloggers.

    Appreciate it!

Leave a Comment

Your email address will not be published. Required fields are marked *