At least for now, if you download the book to your PC (not the PC for Kindle app) using the option for transfer-to-your-Kindle-via-USB on the Manage-your-Content-and-Devices screen at Amazon, the downloaded file will be in AZW3 format.
One thing to check: You wrote that you installed the app and allowed it to sync. Did you also download a DRM protected book from Amazon through the app? That step is required to establish the data that DeDRM uses.
Hey could ya make this process a little more complicated ? It only took me 5 days on and off to export a single book I had bought to EPUB so I could read it on a NOOK LCD reader instead of my phone.
The .pdb file is a database format used for the Palm OS platform (Palm Database). Palm Doc [.PDB], eReader [-er.PDB], Isilo [-is.PDB] are the three most common versions of the PDB format. We will get eBooks in PDB format if we purchase from ereader.com, Fictionwise.com or BN.com.
But here comes another fetal problem. Most PDB books we purchsed and downloaded that aren't free are encrypted with DRM--digital rights management--protection, a machanism that prevents you from using PDB on all your mobile devices. To reslove this problem, you should Remove DRM from PDB at first.
Go to iSilo download page and select your computer system. After installation completed you will find an icon on your computer as the image shows and you will find all your pdb files are with the icon. 2b1af7f3a8