I just flashed the 9-30 FW onto my M701. The procedure is rather different from previously so do read the instructions before proceeding. IMO, the new firmware is much better with a dedicated "home" icon in the status bar, a more responsive touchscreen, default English language and absence of some "redundant" pre-installed apps. According to the update instructions, it is important that you record down your MAC address BEFOREHAND and input it as described in the update procedure. (Hit "menu" in the wifi settings page of your device for your MAC address.) One reason why many people have encountered non-functioning Marketplace is that many are using the SAME sample MAC address listed in the instructions.
Good luck.
Good luck.