Ah! The github readme has the options sections in a collapsed div which resulted in a search for "3.0" not finding this important detail! Now recompiling with SDK_BASE explicitly set. If this works I will look at how we might modify Makefile to add an option for SDK version.
btw this isn't intuitive to me. My SDK is not at the SDK_BASE location.
When I 'git checkout 18.104.22.168' I end up with Sming/Libraries/ITEADLIB_Arduino_Nextion/examples/CompHotspot/CompHotspot_v0_32.HMI changed and I can't subsequently checkout because this file is seen as changed. Any ideas?