Somehow, a book that I had just started reading on my kindle jumped to the end. From that time, all of my Kindle devices showed that the "farthest point read" was that point, and whispersync was effectively broken for that book. Here's how I was able to reset the "last page read" for that book:
- Go to the device where you have the book at the location where you want it to be set (either at the beginning of the book or at a given page)
- On http://www.Amazon.com click My Account > Digital Content > Manage Your Kindle.
- Click "Whispersync Device Synchronization".
- Turn Synchronization Off
- Go back to your Kindle device and "Sync to furthest page read".
- Remove the book from that device.
- Re-download the book from you "cloud". On the kindle, go home and tap "cloud" to find the book.
- Open up the book.
- Go back to "Whispersync Device Synchronization" and turn it back on