Recovering LG Thrill from CM7 to stock - an easy guide.
I recently rooted my LG Thrill (US AT&T) and installed CM7 on it. I didn't backup the original image. The CM7 image had major issues with echo, and not receiving calls. I managed to get back to the stock image after a lot of varied attempts - documenting my experience here in case someone else is facing the same problem.
1. Install the stock, rooted gingerbread image from acidhazard's site. Cannot post links - our firewall doesn't allow access to the site. This image cannot be used because the fonts are totally messed up, though the calls seem to be fine.
2. Follow AT&T and LG's instructions on upgrading to ICS using LG's support tool (this did not work unless the phone had a stock image). Make sure you remove the external SD card.
That's about it. Since the support tool was able to talk to the process on the stock, rooted image the upgrade succeeded. I won't document the various attempts I made to directly flash the kdz file directly - suffice to say, they didn't work.
I lost root after upgrading to the stock ICS - I might try to regain that just to remove AT&T's default installed apps which are just a waste of space and memory. But I'll do a lot more research before that :P