Hm, the big file shouldn't cause bricking, as long as you use the correct one for your hardware (Wifi vs. Basic). I assume you have the Basic since with Wifi you could just update over the air?
Did you disconnect the reader without properly ejecting / umounting the USB storage first? If so the file may have been corrupted on the reader, which in turn could be what caused the bricking. Always eject properly and check that the firmware file has the correct size after you copied it on the reader. If you want to make absolutely sure, I guess you could copy it under a different name so the reader won't start updating right away, eject/disconnect/reconnect, verify file size and checksum, and then rename it, eject it, update.
The device itself unfortunately does not do a proper verification of the firmware file. If it was properly made, a bricking of whatever kind should simply not be possible.
The only other thing that comes to mind is that you should never fill the internal storage to capacity. The reader needs some free space there so it can recreate its book database properly and have room for other operations also. Although unless you copied thousand books on your reader the very first day that can't have been your problem either.
Good luck with the replacement device!
Last edited by frostschutz; 12-30-2011 at 08:05 AM.