Okay, a few things:
* Vanilla 3.2.1 users, please check
yifanlu's latest jailbreak

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* Once and for all, the goal of the screensavers hack is to allow custom images on *regular* Kindles, it doesn't, and will never 'help' you bypassing something you agreed to (ads).
@Moosher: What's the error code shown on the bottom of the screen when the update fails?
@just: No idea, sorry

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