Inside iPhone 3.0's Remote Wipe feature | iPhone | iPhone Central | Macworld - http://www.macworld.com/article...
Jul 16, 2009
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"The time it takes to “wipe” an iPhone or iPod touch varies greatly depending on the model. When I sent the wipe command to an iPhone 3GS, it took a minute or less for the process to complete. But when I sent the command to an older iPhone or to any iPod touch, it took more than two hours."
- Philip Lei