96XX Series phones corrupt firmware file?

[gphone]

We have about 500 9620 IP sets and for some reason some will lose connectivity with the system and won't come back up. The phone just sits on Discover. I don't think anything is really wrong with the phone It's as if the firmware file is corrupt or something but the phone won't download a new file as one exists in the phone already. I've been told we can update all phones at once but not on an individual basis. Since these are new I've been returning them for repair but since its happened to about 10 of them over the past few months its getting a bit frustrating and what will happen when they're not under warranty any more? I've also been told that the 46xx phones had the same problem. Is this true?
Suggestions??

 

[WimW]

I have had 1 9620 station that had the same problem as described above. After investigation I saw that it just loses the default gateway setting even if you set it to manual. I had to send it repair because I could not resolve the issue myself.