I upgraded from Cyanogen 6.1.1 to 6.1.2 a few days ago (used ROM Manger). I did not clear cache or remove programs. Everything else seems to be working fine although I did have to re-register my Swype beta.
If I turn on my wireless, it doesn't see ANY access points near me. Usually I see mine and several of my neighbors.
I was hoping I could just install the updated ROM since I was running Cyanogen previously, but just wanted to check with the forum and see if there's anything I can do short of reinstalling the ROM and clearing all cache and data?