Looks like there are a lot of hits on Google for 'failed to find byte code' for all sorts of libraries - according to SO this is a bug with Android Studio 3.1 and the workaround is to disable instant run. I haven't seen this myself but I don't think it is specific to the EMDK.
Hope that helps.
Perfect - thanks!
Steps to disable the Instant Run :
1. Navigate to File > Settings from the menu bar (Windows or Linux).
On Mac OSX, select Android Studio > Preferences from the menu bar.
2. Navigate to Build, Execution, Deployment > Instant Run.
3. Uncheck the check-box next to "Enable the Instant Run to hot swap code/resource changes on deploy"