Ubiquity is the livecd installer for Ubuntu. We need to make a few changes to this.

The first is to change the mirror locations so that they point to us rather than Ubuntu. We default to having universe and security enabled. For simplicity, this isn't controllable via debconf (unlike Ubuntu). We also disable the check that a valid sources.list has been generated, as this seems to require that it is accessible via a network. If it isn't, the installer crashes out.

Interestingly it expects a restricted kernel to be always available (crashing out otherwise). A one line change fixes this.

We also change the ubiquity icon to replace the Ubuntu logo with our own.