This was the case when I decided I wanted to jailbreak my Kindle for the sake of changing the screensaver images from those provided by Amazon to those of my own choosing. It seemed simple and straightforward enough; download the install-bundle, find the one applying to the specific firmware version my Kindle was running (which you find by going to the Settings page on the device). Except the specific install I needed wasn't included in the main bundle.
Now, part of that was my own fault as I had missed the part of the credits at the top of the thread that specifically mentioned (and linked the specific install files for) the version I had (3.2.1), but at the same time I don't understand why the main bundle couldn't have been updated to include those installs (or at least mention that little fact in the installation guide further down in the thread). Thankfully, once I actually did find the correct install and ran it, it worked. And the screensaver hack installed without a problem (the only issue was figuring out how to get the new images to function).
Part 1: Jailbreaking the Device
|Don't you just love my new screensaver?|
dx = a Kindle DX
dxg = a Kindle DX Graphite
k1, k2, k3 or k4 = Kindle and which main firmware version it's running
g = a Kindle with 3G internet
w = a Kindle with wifi, but not 3G
gb = UK version of a Kindle
i = International version of a Kindle
Now, I have a Kindle 3.2.1 with 3G internet on it, meaning the install file I was looking for was coded as k3g_install at the end. Go and do Steps 2 through 5 listed further up.