Kindle Sync with non-Amazon eBooks on Windows

Thanks to DiapDealer for teaching me this trick! Also thank you to m0ngr31, for discovering that the ASIN from a pBook will also work! Another thank you to Kerenon for testing and showing that this trick worked with a fake ASIN number. You can read more about it in the thread Sideloading and Whispersync.

Have you purchased downloaded a freebie ebook from a retailer other than the Amazon Kindle store? Would you like to be able to sync that DRM-free ebook among your Kindles and Kindle for PC (K4PC)? If that same book is also sold at Amazon and has an ASIN number (eBook or pBook), we have a little trick using the Mobi2Mobi GUI to help you get your sync on. Unfortunately, at this time, this guide shows a Windows only trick. Also it only works for syncing to the furthest page read (no bookmarks, notes or highlights will sync).

Per DiapDealer: "For the record, the same thing can be done on Linux and Mac machines that have the MobiPerl Tools installed... 
it would just have to be done with the command-line version of mobi2mobi as there is no gui. Definitely a PITA for some, 
but still do-able. :)"

Note: m0ngr31 has created a script to find and download the correct ASIN when available or generate a useable 
fake ASIN if no proper number can be found. Please check out the Auto loading meta data from Amazon thread for instructions.

1) Download and install the Mobi2Mobi GUI and all the required files.

2) If your DRM-free ebook is not in .azw/.mobi/.prc format, use Calibre to convert it.

3) Open the Mobi2Mobi GUI and provide the information on where to find the mobiperl tools and where your DRM-free ebook is located.

4) Open the book in the GUI.

5) Go to "exth type", use the dropdown box and find "113 - ASIN" fill in the ASIN number in the box to the right marked "exth data" (Find the book in the Kindle Store then look under "Product Details" for the ASIN number. If the eBook is not in the store, look for a pBook version). Make sure to click the check box to the right. Click the "convert button".

6) After the conversion go back to "exth type, use the dropdown box and find "501 - CDEContentType". In the "exth data" box type "EBOK", click the check box to the right and then click the "convert" button again.

7) Close the GUI and open your book with the Kindle for PC app. (If you have a Mac, you could open the new book in Kindle for Mac but all the EXTH work has to be done on a Windows machine... for now).

8) Load the same book on your Kindle via the USB cable (do not send it to your Kindle via Whispernet as it will undo all the work you've just done).

9) Read, read, read on either your Kindle or K4PC (I'm starting with my Kindle first). Close the book, make sure your wireless is on and from the home page use Menu > "Sync & check for items" (we're doing this just to make sure we've set up everything correctly, you should not have to do this again for this eBook).

10) Open your book on K4PC and right away (if you're connected to the internet), you'll see a dialog box asking you if you want to "Sync to the furthest page read", click that button to confirm. Voila, you're done!

11) If you had started your eBook on K4PC you would see the following dialog box on your Kindle when you open the eBook (your wireless must be on and you may have to force a sync if it doesn't update right away):