We've already seen how on LG and Samsung phones, accessing the diagnostic menu can allow one to enable USB tethering. Now it is becoming evident that we can run unmanaged, native code on our phones too. Well kind of.
First, unmanaged, native code just means direct access to the software systems e.g. phone, email, etc., not just Silverlight applications that 3rd parties use. Second, the requirement here is you need to be able to sideload apps and only developers who pay the $99 fee get access to that feature. However, we've already heard from one of our sources that the whole "unlocking" business is tied to a single registry edit, meaning it may not be hard to circumvent at all.
What this all means is this: we may, at some point, be able to load custom software that not only is not approved by Microsoft, but changes fundamental restrictions on the device as well. In addition, changes to Metro UI may be possible. Of course, we won't be able to distribute these through the Marketplace, so you'll have to have the iPhone-model of a Cydia-like store. Cydia is the non-approved Apple App store where all the "hacks" and non-approved software are distributed. We so no reason why this won't happen eventually for Windows Phone either.
All of this comes back to what happened today with Australian developer Chris Walshie who was able to run unmanaged, native code on his device. The file modified “Microsoft.Phone.InteropServices” which may allow COM access in the future. By being able to modify that and write into a program, he was able to do something that only Microsoft, carriers and OEMs could do. In other words, today was the 1st day and 1st big step in "freeing" our phones.