Originally Posted by kovidgoyal
I'd like confirmation on whether sub folders work or not, as I would be fairly surprised if they did not. Also could someone create a news download in calibre (with output profile set to Kindle) and copy the resulting mobi to the fire and see what happens.
Sub folders work, Kovid. I had [PDOC] set as a conversion option under mobi output. This caused the Fire to read it as a Document, rather than book. Reconversion with this removed causes proper behavior. I'll be back in a second with the news result.