My iOS game launches fine on GSM but won't run on CDMA

Question

We built a game (that's a couple of weeks away from being submitted to Apple) and all this time we've been play testing / debugging on GSM phones (AT&T). One of use got a new iPhone 4 on Verizon. When he's on the 3G network, the game will launch to menu but if the use pushes "Play" nothing happens. However, if he joins a wi-fi network then pushes Play the game starts normally.

Has anyone encountered anything like this? We're fairly certain it's a software issue but have been searching the Internet for any info on what exactly the issue is.

Answer 1

We found out the problem! We changed ports. CDMA (Verizon) doesn't like port 4444, so we changed to another (random) one of 32545 and success! Thanks to everyone and remember kids, CDMA doesn't work on port 4444.

Answer 2

You need to figure out what specifically in your app is causing the game to fail to start. If you are not getting anything logged then there is presumably an error that is not being handled.

Given starting a game requires geolocation, my guess is that on the Verizon phone getting an accurate location fix is taking longer than your app expects and it is silently timing out, or that it is initially returning a location of 0.00000000, 0.00000000 and your app isn't liking that. When on Wifi, location services may be providing an instant initial estimate of location based on the known location of the Wifi network, which would then avoid the issue.

One way to test this would be to hardcode the location or seed an initial location into the app on launch, and see if this fixes the issue.