The mp3 jailbreak does not use the kindle update restart, and does not display the update screen. It makes no changes to the main boot partition except adding an update key. This key allows the "update your kindle" menu item to be enabled in the settings menu when an update package for your kindle model and using that key is on your kindle USB drive. That is all the mp3 jailbreak does, unless you have a runme.sh script file on your USB drive, which it will run if it exists. Did you happen to have a runme.sh on your kindle USB drive?
In your case, the mp3 jailbreak displayed the "freed" image, which means that it successfully installed the new update key. The only other way to know it worked besides the "freed" display is that it enables the "Update your kindle" menu item it an update package is on your kindle USB Drive.
The ixtab jailbreaks that you tried use the data.tar.gz method, and they also install this update key.
The update*.bin installers that you can install after doing a jailbreak can make changes to the main boot partition root, but they should be well tested and safe for your kindle.
If you install any packages that use the data.tar.gz installation method, their safety and reliability depends entirely on where you got them. I examined the packages at both links that you provided above. They look safe to me.
Are you sure you did not previously install something else that may be causing this problem? Did you have a runme.sh on your kindle USB drive when you ran the mp3 jailbreak? If so, what did it do?
Last edited by geekmaster; 01-29-2012 at 12:27 PM.