So, one singularly unfortunate design flaw of the Sony Reader is that it appears to implement the USB standard to the letter. Specifically, before it will draw power over USB for charging, it must negotiate with the controller on the other end. If no such controller exists, it just sits there in USB mode, draining battery, when it is supposed to be charging.

This happened a couple of weeks ago, when I innocently plugged the Reader into my iPhone power brick. I came back a couple of hours later to find a thoroughly dead device.

Poking around some forums, I found the solution. I ordered this, and it just arrived. And it works! Yay!