Going by the experience I'm just having, I would advise against upgrading firmware unless you have good reason to do so and preferably have an "escape route".

I had recently upgraded my router firmware to resolve an occasional ADSL problem. That went fine but otherwise I have left things alone.

Having read this thread, I decided to check on my wireless adapter and decided to upgrade. The upgrade has gone wrong and the adapter is determined it has an IP address of 1.0.0.0 and some of the other fields just contain nonsense. The utility program is refusing to allow me to save any changes. If I'm lucky, I will find a way round it in time but at the moment, I have a piece of junk created by me for no good reason.