Still investigating but ATM it looks like some of the PDFs I've been annotating on the DPT-1 are being corrupted.  Not so badly that they can't be opened by a number of viewers, but bad enough so that some programs will refuse to process the content.  I haven't yet come across any other reports of this so for all I know it may be some kind of pilot error ;)

After trying a few things, I've found that using the mutool command line tool via its "clean" subcommand seems to fix things (at least in limited testing).  Came across mutool while reading the mupdf man page :)

gs (from the same folks) seems to be able to repair as well though IIUC one's annotations may get lost in the process -- that might be specific to the way I've been invoking gs though, so there may be better ways.

Some notes for future reference :)

Succeeded in updated the firmware to 1.5.x by:

1. Unzipping the .exe file representing the update
2. Copying the DPT-S1 Updater.package file (one of the extracted files) to the root directory of the DPT-1's internal memory
3. Performing a recovery restart of the device via the Testmode app (see http://www.mobileread.com/forums/showthread.php?t=235661)

After a somewhat lengthy wait, the update seemed to complete.

Appreciate being able to navigate to different pages while maintaining the current zoom level.

you could edit the ini file to have it not start minimized.

-mouser (December 27, 2015, 09:41 PM)

I took a look at the two .ini files that I found but it wasn't obvious to me what change ought to be made.  Any hints?  (FWIW, this was for the portable version.)