Install boot-menu, which will allow you to boot other OSes:

• Guide for generation 8 Android devices: 28, 32, 43, 70, 101 Internet Tablets;
• Guide for generation 7 Android device: Archos 5 Internet Tablet;
• Guide for generation 6 devices: Archos 5 and 7 Internet Media Tablets.

Now you can enjoy using it.
If you run into problems, you should check if we know already and report them if necessary
and can seek help on  #openpma on irc.freenode.net.