Before selling my 3GS I filled it with music to overwrite data. Then I did a Erase Content and Settings. Any benefit of filling it with music, or is it just as good to do an Erase Content and Settings? BTW, I had iTunes do an automatic fill-up, but still there was about 420 MB that couldn't be filled-up/used. Is that remaining 420MB or so the iOS? The buyer then told me he wanted to check the 3GS's serial number and see for sure it was a 32GB 3GS so I re-activated it. With the re-activated 3GS could the buyer find out my phone number or get any data, personal data or otherwise? Thanks for any info!