PocketMatrix

Windows CE 4 default resolution is 240x320. You have to simply add a stupid resource to your project, in order to let the OS know that he has to switch to 480x640. The resource name is HI_RES_AWARE. Google for that, you'll find some explains.

I read on Hybrid forum that you are using their implemention: don't bother, hi-res works seamlessly once you add this resource and create a 480x640 window (and only that: full-screen opengl, no windowed mode with Gerbera [at least, if it is possible pls explain me how... ]).