Exactly that is the purpose of this Kickstartswitcher. You put both KickRoms in the Kickswitch and then install the Kickswitch instead of your ROM in the corresponding socket of your A500.
I have bid on it

Switching to kickstart 3.1 is VERY useful for my A500..it allows me to run apps, format and rename disk on AExplorer without flipping disks...open up new possible features I do not have with kickstart 1.3. I will leave kickstart 1.3 for backward compatibility games
