Hi, one of the older jailbreaking methods used this kind of thing, so I imagine it might be easy for amazon to fix, but I have no ideal how long it lasted.
If you havent seen it, I'm sure you can find the threads on here somewhere, but this github page seems to have a good description, and its what I got with google searching.
https://github.com/sgayou/kindle-5.6...rashing-webkit
This guy says that the bugs were delivered to amazon, and fixed, so that's something.
I would love it if someone could find a new real jailbreak method that doesn't rely on the fragile system we have found to do it with the factory images.