You may be hoping to subsidize the purchase of an iPhone 3G with the sale of your old one, but since you should wipe all your personal data from the old one first, we brought you [Rich Mogull]’s method for wiping all your private data off of an iPhone. The method, which involves overwriting your data with music, is slightly flawed, mainly because of live files that can’t be deleted while the phone’s OS is working and because the OS reserves a portion of the hard drive as unwritable space, which will make it impossible to completely fill it with music.
For those looking to annihilate every scrap of personal information, check out [Jonathan Zdziarski]’s method. It involves restoring the phone as a new phone, then jailbreaking it. Once the user has shell access, umount is used to force the two mount points into read-only mode. Now the partitions can be overwritten with /dev/zero, which should wipe them clean. The phone should then be forced into recovery mode to perform another full system restore, and the process is complete. As [Zdziarski] notes, several iterations of the process with /dev/random should prevent even NAND recovery, but there is an even better way of ensuring full data destruction: “simply take a sledgehammer to the device.” If you are unfamiliar with the command line though, chances are [Rich Mogull]’s method will be easier for you to handle, but don’t blame us if you sell your phone and the Feds get wise to the evidence you left on it.