As you may already know, there is unfixed critical bug in all OS2006 firmwares causing random memory corruption during WLAN use. Symptoms may be random application or system crashes, corrupted data in RAM or files and even reboot loop if you are extremely unlucky.
Further details here:
http://www.internettablettalk.com/forums/showthread.php?t=11824
All Nokia 770 users are advised to check it and consider installing this bugfix for better device stability.
Lets hope there are no other bugs added and this fix is really effective ;-)