3650 hangs on startup

Hello friends,
My 6 weeks old 3650 is hanging on startup. The Nokia logo and
the keyboard flashes 3-4 times and then the phone dies. I have
tried removing mmc, safe mode reboot (pencil button hold).
Nothing works!

Talked to AT&T rep and he told me that they can send me a
refurbished replacement. Other option I have is to get
it reflashed from Nokia Service Center. Perhaps will go for the
later one because the phone is unlocked.

BTW: Can anyone really verify that unlocking (remote)
really voids the warranty (AT&T USA)? In this case when the
phone is not booting, how can they find if the phone is locked or
not?

I saw lots of posting re. similar problem. Honestly looks like
Nokia shipped 3650 in a hurry (to beat P800?)

I did a quick search on 3650 flasher cable...didn't find anything
on Ebay. Has anyone tried it? I have some experience with
DCT3 phones. Never tried DCT4 cables though.

Any pointers will be appreciated

BR
-iknow (not really!)