[GeoffR]

I don't think it is normal for the device to completely freeze at random, that probably means a hardware fault.

The last time my Glo froze completely was with firmware 2.1.5, over a year ago. I put that down to a firmware fault because it always happened in the same place, when using the font settings menu in a book.

There have been a couple of times since where it has appeared to freeze: sometimes during sync the spinner stops spining and there is no response to the touch screen or light button, but it recovers after 10-15 seconds and completes the sync; a similar thing happens sometimes when I unplug the Glo from the USB cable, it can take 30 seconds or so before it realizes it has been unplugged, but it resumes normally if I wait for it.

Edit: One other situation where it seemed to freeze but then recovered was with some books that had enormous .html files, mainly omnibus editions where the publisher had put a whole book into one .html file instead of splitting it up into one file per chapter. With these sorts of books page turning is very slow, and when using the TOC the device would freeze for 10 seconds or so. Running the book through Calibre splits the huge files up into smaller files which fixed the problem.