ALrighty then:
Backed up & Hard Reset. Synced all my schtuff back in. Loaded 1.6 MSVC first and voila', worked a treat
After loading all the junk back in (Tweak2k2, HTC Customizer, RC Mod, QuickMenu) I discovered that MSVC doesn't "like" bein on the "press & Hold" button, so I have it on an instantaneous button. And it only occasionally beeps to start....it does start, you just get no notification. So something is conflicting. It does run even if there's no beep; you just assume its running, talk in & off it goes, so thats nice.