Mar 5, 2008

Fixing iPhone signal loss

Yesterday, Scott forwarded me along a question from TUAW reader John Stuart. He wrote in asking about his cell signal. When put on sleep/hold, the signal fades out and he can't receive calls. His phone is unlocked and in the UK, and this signal loss appears to be a common fault.

As a temporary measure, John started playing back music on repeat, with the volume cut off. As you might imagine, this runs down the battery and prevents him from actually using the iPod features without having to do extra work.

TUAW to the rescue. After polling the developer community, ApolloIM developer Alex "Arminius" Schaefer came to the rescue. He remembered that SummerBoard supported a mode that would retain your signal even in sleep mode.

The hack works like this: You install SummerBoard (it is available via and then create a temporary file called SummerBoard.DisablePowerManagement. Once created, SummerBoard sees this file and keeps the signal from powering down.

With this knowledge in hand, I was able to create a small utility for John, which is hosted here. To use, just tap it each time you reboot your iPhone. It creates the temporary file, which lasts until your next reboot. (All tmp files are deleted then.)

The JohnTool application will be available in short order via and is already available at the PXL package repository.

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