In current version, when stubbing out EWR, the system will always raise a "not implemented" exception on system power up coming from Microsoft.SPOT.IO.dll. While the system continue running safely after, seeing this exception is disliked by users and we always receive the same question "why this exception?"
Removing EWR dependency out of the internal libs will be ideal and if using EWR is a must then at least we need a way so there is no exception showing on power up.
An example
http://www.tinyclr.com/forum/topic?id=7547
Gus - GHI Electronics