What are the potential issues of jail-breaking to test the new background APIs on a 3G?

Question

I've registered/paid for the iPhone developer program, which allows me to test apps on a device. I have an old 3G that I would like to use. However, I'm interested in using the significant change notifications as well as it working in the background.

If I were to jailbreak to enable background processing and things like that, what issues could I have, and how likely are they to arise?

EDIT: I actually do have an iPhone4, but I'm using it for my personal phone. I've heard that it's not to great of an idea to use your everyday phone as a development device. I've done a little more reading, looks like I could use Ad-Hoc distribution to test while avoiding the problems of using your primary phone as a development device. Seems like the only downside of this would be no debug info, other than logs.

Answer 1

iOS 4 has been hacked to allow home screen wallpapers and multitasking on iPhone 3G. (http://pixelatedgeek.com/2010/06/ios4-jailbreak-and-multitasking-now-available-for-iphone-3g/)

It seems to be running fine without any issues, probably not as fast as an iPhone 3GS or iPhone 4.

Just be careful if you use this as your main testing device and make sure you test on supported hardware before releasing. Personally, I'd use something that was 100% supported to be sure everything worked as expected. However, if you don't own a supported device this may not be possible.

Again, make sure you test on friends 3GS or 4 before releasing. I don't foresee any major issues, but testing features on hardware that isn't officially supported could cause problems.

Update: I've used my phone for development purposes before and haven't run into any earth shattering problems. If an issue comes up you can always restores your device.

Answer 2

If you are planning to target iOS4 you really, really really should spring for an iPhone4. You can understand how things will run on it, and also be able to see how the higher resolution display interacts with your app. I'm not sure running iOS4 on a hacked 3G will tell you much more than running in the simulator, and in fact because of the reduced memory may show some issues that just do not occur on real devices.

One other great option is a recent generation Touch. Although it doesn't give you the display to check against it is a good test platform for multitasking.