Orijinal gönderinin sahibi: Justin

Metin:

I have had this problem and as a trial swapped battery's with an identical iPhone 4 the phone worked fine then, I then put the old battery into the other phone and the error/ unable to boot up occurred so a new battery will resolve error 21 or other similar boot up problems and is a cheap fix £2.50-£3.50 on e-bay.

Durum:

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