After waiting for over a week for replies, I finally tackled this myself, via:
sudo dd bs=512 if=/dev/sdb of=/mybackup/PRST1.img conv=noerror,notrunc,sync
I got only 7 errors, so a total of 3.5kb was uncopyable, but in the end I got my 2GB image file. After erasing the partition table, I tried to restore the image I made, but that failed at 482MB, this time, any of the options (sync,notrunc,noerror) didn't help.
And so I was screwed - or so I thought.
One interesting thing to note is that restoring ended at:
941745+0 records in
941744+0 records out
...with the counter being 1 record off.
Anyway, to my surprise I saw that, despite of 75% of the restore failing (?), in Gparted all the partitions were there again. So I downloaded partitions sdb 1,2,5,6,7 from entodoays' post and restored those without issues (using dd).
Then, just to see what happens, I ran:
sudo dd if=/dev/sdb of=/mybackup/PRST1.img
...and to my utter surprise, it went through completely without errors.
Unplugged everything, restarted the reader, uploaded a couple of books, and the device still works. I can even read books!
I really have no clue why the device isn't actually bricked now, let alone if the original issues are fixed. Just posting these tidbits since they may be helpful to others.