I tried for HOURS to get the ad-supported K3 to jailbreak with no luck. I removed all my books and tried the restart hack over and over and it never worked. I posted on Amazon's forum in a thread specifically talking about wanting to be able to pay $25 to be upgraded from the ad-supported Kindle and got a bunch of pretentious responses from people saying that it was my fault for not researching Kindles online before buying one. Long story short, I could only see the front of the boxes in their locked case and I didn't know there was an ad-supported device, I asked the guy with the key to the case why one was cheaper and he told me it was because one was an older model. So yeah - not really my fault, either way...not the purpose of the thread.
I ended up returning the Ad-Supported Kindle and bought the ad-free version directly from Amazon. It was on my doorstep in less than 24 hours. I was shocked.
I just now got the jailbreak and screensaver hacks to work on my K3 Wifi with v3.2.1!!! It took a couple tries and I had to remove my books, but IT WORKED!
I used Kindle-3.2.1-jailbreak-0.5 (follow the read-me file instructions exactly)
and also I used the kindle-ss-0.22.N screensaver hack.
I was getting U007 error when trying to jailbreak before I removed all my books. You have to restart via the menu screen
, wait for it to begin restarting/loading, and then plug it in. Make sure you already have the proper bin file copied to your clipboard so that you can quickly paste it into the root folder once it pops up on your PC. After you paste it unplug the usb and immediately navigate to menu>settings>menu>update your kindle>ok
I'm not sure how fast you have to be, but as fast as possible seemed to work for me.