iOS 4.0.1 concerns

[noluck]

I received, a couple of days ago, my iPhone 4.
I upgraded directly to iOS 4.0.1.

I was surprised to see than in some areas (not everywhere, usually indoor) I get "no service" and therefore unable to make calls or surf Internet whereas my friends, still running iOs 4.0, get a full strength signal (5 bars) and are able to call and browse internet without problem.

Would it be possible that they changed more that just the bars display?
Or maybe my phone has a faulty hardware? Though I do get 5 bars signals as well

For information I'm in Tokyo.

EDIT: It seems there is a similar issue reported on the apple forums, people upgrading their 3GS with iOS 4.0.1 and getting no service in some areas as well: http://discussions.apple.com/thread.jspa?messageID=11919454

EDIT2: My friends have an iPhone 4 as well same model 32G, the only apparent difference is the version of iOS.
In Japan there is only one carrier supporting the iPhone yet: Softbank

 

[noluck]

Is anyone having a similar issue with the iPhone 4?
Or is it an isolated problem?

 

[noluck]

Here is a picture took in a restaurant (indoor).
I got no service whereas my friend would get a fluctuating 3 to 5 bars (and can make call and access Internet).
See attached screenshot.

PS: I do get reception in some indoor places as well, but less often than the phone running ios4

 

[iStalkApple]

I may be no help but here is a tip. Do not upgrade till you see flaws. I was about to update to iOS 4.0.1 till I heard these and said no. I also upgraded my dads phone to it and his 3Gs is dead slow. He hates it.

 

[bluer101]

I'm waiting also for the next one. After that update has been out then I will upgrade if no problems are found. I have done this every time since I got my original iPhone in 2007. Sometimes I will wait months to update.

 

[Consultant]

Try restore to 4.0.1. If that doesn't help,

Make genius bar appointment
backup iphone
you can probably get an exchange

4.0.1 works fine here.

 

[noluck]

Thanks

Maybe it's just my phone then.