Microsoft had cautioned users regarding updating their phones and said that they would not be able to update their phones past the unofficial version – NoDo (7390). Many users have claimed that the unofficial update mechanism has worked well for them. But that they would not be able to update it past that.
NoDo, No No, Not Yet
Through their official update mechanism, Windows Phone update build 7392 will be going out to phones. Those users who have used the unofficial build 7930 would require an official build to update their handsets. They went on to say that the unofficial method does not contain an official software image and hence cannot be updated additionally at this time.
Brandon Watson, a senior director in the Windows Phone group, said that due to scheduling of engineering resources they do not anticipate having to undo the changes made to phones by these unsupported methods. They are not ruling out having a fix in the future but for now there would be no fix and that their engineering priorities are focused on improving the process by which updates get to Windows Phone.
Chris Walsh released the unofficial update tool that people could use to force updates to their Windows Phone 7 devices which included an ability among others to cut and paste. Walsh however thinks he has created a way to get the phones back on an officially supported path. Watson confirmed this and said that Microsoft will work with him to validate this solution.
The 7392, a post NoDo improvement fixes bogus security certificates on handsets and nothing else
Source: The Windows Blog