Saturday, September 29, 2007 [Tweets] [Favorites]

State of the iPhone

Rainer Brockerhoff:

Consider, now, the software update process. It assumes that the iPhone’s various processors and firmware(s) are in one of the known states—indeed, this is required for the complex cooperation required for uploading new software. If this cooperation is disrupted, the update may not begin—leading to an error message—or, worse, it may begin but not conclude properly. At this point, one or more of the iPhones processors may try to enter a recovery routine, either wiping the flash memories or to reinitialize them to a known state. No doubt this will be successful in most cases, and the new update will then be installable on a second attempt. However, the recovery may fail—since the exact circumstances couldn’t be foreseen—or it may be assuming false preconditions (like, a valid AT&T SIM card being present). The system will probably try to recover at successively lower states until falling back to the “can’t think of anything more, take me back to the factory” mode; or it may even lock up and “brick.”

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