Thanks @alexandros, @andrei. That looks like just what I need.
I have the Freescale SoloLite EVK on the way to take a look at next week, but in the meantime I thought I’d have a look at building for the Boundary Devices Nitrogen6 Lite (somewhat counter-intuitively based on the Solo part) as I have one to hand.
Unfortunately I seem to be failing at the first hurdle as both my own builds and the downloadable image from BD seem to block on u-boot startup with a spinner (pic attached). I may need to go back to Boundary Devices about this but wondered if you’d seen anything similar?