Folks, please, just use an adapter specifically for 1.8v, low-voltage cmos interface.
Others on this forum have used 3.3v and even 5.0v, low-voltage interface adapters without reporting any damage to the Kindle.
But the SoC hardware reference manual says: "1.8v" without any "5.0v (or 3.3v ) tolerant" qualification.
Since I am not in the position to purchase burned out Kindles, burned out by following my directions, I do not recommend using anything other than what the manufacturer claims is correct.
= = = = =
Now that the Kindle Rx <- Adapter Tx has a voltage devider on it ...
How do you plan to make the Kindle Tx -> Adapter Rx rise high enough for the adapter to recognize the level as a 'high' level?
(geekmaster had a pull-up system engineered into his diagrammed level shifter for a reason.
)