(Please only mess with your Kindle at your own risk; I've heard it's very difficult to brick it by doing this but the chances are never zero)
^This worked well for me for the actual jailbreak itself, but I had to adapt the process of installing KUAL/Koreader a little bit because of the age of my specific Kindle. (I will probably make a guide to that if I can reverse-engineer what I actually did haha.)
^For now these will only work for jailbroken PW and PW2 models with the screensaver hack already installed