Are you able to find the original rom by doing the following:
Install Microsoft's Network Monitor** (its free - netmon from now on, im lazy )
http://www.microsoft.com/downloads/d...displaylang=en
Close all your browser windows, instant messenger, email, anything that uses the network should be stopped while you do this.
Start netmon, and tell it to capture all the traffic on your network card.
Then start the lg-updater program (get it from lg directly), and have it check for updates for your phone.
Go back to network monitor and stop capturing traffic when it's done.
**If you're familiar with wireshark you could use that instead of netmon.
*Credit for write-up goes to xdapants on xda.*