You should be able to swap back and forth by simply deleting or re-adding this parameter. I've tried both setups on a single data.img and it worked every time.
Just booted with the new kernel and played some audio which worked FINE, as expected. Everything still working (exept GPS since i'm back to GBX0A again).
As for the buttons, I'll try it out later, but i'm sort of used to how it's set without the startup mod. And if i just call that one button 'Toolshed' instead of 'Home' it's all very straightforward.
And from past experiences i see no reason not to take your word for it. Thanks again!