YES! Ever since buying a used 770 I have dreaded the possibility of touching the "Lock device" option by mistake. Your grep command worked perfectly, returning the lock code set by the previous owner (and not known to the eBay merchant who sold the 770).

I tried to include your command in the quote, but it did not carry over. Here it is in a more readable font. It has to be run as root.

sudo gainroot
grep -A 13 lock_code /dev/mtd1 | tail -1

Thanks again