A few days ago the NVIDIA Shield Portable got software upgrade 101, an optional update to help enhance emulator performance.
Emulator problems experienced by some Shield Portable owners should be resolved via this patch. Specifically refresh issues on multiple emulators were addressed.
This update does not bring Android 5.0 to the Shield Portable, as stated on the official Shield Portable section of the GeForce forums. In their word's: "It’s taking us a little longer than we’d hoped, but we are still committed to it and will update you once we are closer to the release date." Of course DroidGamers will be there to let you know when that update is released.