Failed to add device ios 4.2.1 xcode 4 "unknown ios detected"

I have a problem when adding a device Xcode 4 gives an error "unknown ios detected". For fixing that xcode requires none jailbreaked device (iphone 3g) to 4.2.1.

If you have installed xcode iphone and then you shoul开发者_开发百科d have directory:

/Developer/Platforms/iPhoneOS.platform/DeviceSupport/4.2.1 (8C148)

I need this file folder. I would appreciate if you share it.

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Generally that error occurs when the OS version on the device is greater than what you have support for in XCode. You will see the same thing if trying to install to a device running the new iOS 5 beta from the standard XCode version. Try updating Xcode to support your version, or copy that OS version to Xcode.

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I had a problem adding a ios 13 device (not relevant I think) the device would flash show itself a couple of minutes and then vanished. The problem was fixed by using anther USB port