Sweet! I got it working. Instead of just taking out [PDOC] I changed it to [EBOK] and it did the trick. Someone mentioned this in the thread gweminence linked above.
Originally Posted by gweminence
Blossom or SamL (Or anyone using Fire with Calibre), I wonder if you might take a minute to confirm something that will potentially help Kovid. I noticed that (after updating and using calibre to send a book to my Fire) a second connection AFTER sending a book, does not result in calibre detecting the book(s) I sent to the device on the first connection. So if you wanted to try that, then post your findings here:
It might help to get this resolved. Or, at least, tell me that the problem is my end.
Calibre seem to noticed that the book did indeed go to my device. I'll post this there too.