Just curious - Alex - why do you want to have 2 Win 8 bootable partitions/drives?
If it for maintaining 2 versions based on Windows Services, then I may have something for you to look at as an alternative.
I have been a programmer since you don't want to know, and I wrote 2 little C# utilities that allow me to create 'profiles' of Windows Services and of Start Items that I want to be able to dynamically disable/enable for either configuring for audio processing or for general processing.
A Profile of Services would include a list of all of the Services I want to control, and when disabling Services using a Profile, Windows marches down the list, saves the current start up type for each Service in the profile, then sets the start type of those Services to disabled. Enabling Services would reset each Service's original Start Type from the saved values.
All of the control through these profiles is quite simple, and only takes a couple of mouse clicks.
If you think that would work for you, please send me a private message with an email address and I will zip up and send you the code and the executable. No installation is required, you just need to create a shortcut and run. (even has a Test function)
I have used Service Manager and Start Item Manager for several years, for controlling services and start items for purposes of live performance versus general use.
Bob Bone