Erasing Data From Jailbroken 3G on 3.1.2

[bigstu22]

About to sell my jailbroken iphone 3G and I want to erase data. I've done some googling on this and even though there are quite a few other threads, there seems to be no definitve answer.

I certainly don't just want to 'erase all content and settings' from the phone itself as I've read of others having real problems with that.

FYI, I bought the phone already jailbroken so I don't know what jailbreak alternative was used and I don't have any of these SHSH file thingies saved.

I'm thinking I might have to manually remove data and then use ierase to 'zero' any free space afterwards.

Any advice would be greatly appreciated

[CaptainChaos]

You do not need any SHSH on file for the 3G unless you move up to 4.0. So basically you should download a stock 3.1.3 from MMIs Downloads section and press Shift/Restore, then select the 3.1.3 firmware you downloaded. Afterwards, set it up as a new phone and uncheck everything that iTunes wants to sync(contacts, email, notes, calendars, etc). Press apply and you have a working phone with nothing installed that pertains to your personal data.

[bigstu22]

You, sir, are a gentleman. Thank you!