I did this last night and it worked well. Its a little harder that just plugging in to Zune but if you are tired of waiting and are a little adventures go for it I did. For me it worked as advertised was fairly simple to do. I will be testing this week and will report back on the results.
Link > How to force update Nokia Lumia 800 to latest firmware 12070 | SymbianTweet
Link > How to force update Nokia Lumia 800 to latest firmware 12070 | SymbianTweet