@dhdurgee: By clicking on the 'send us $20' link in your Manage My Devices (or whatever it's now called) page on your Amazon account to unsubscribe to Special Offers

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Since a FW update wipes mostly everything, you'll want to do the update *before* installing other stuff. That said, if this is your first foray into custom Kindle stuff, I'd still recommend familiarizing yourself with everything on FW 5.6.5 before moving on to a less friendly FW version.