I'm having the same issue. I booted out of an image running on the SD before popping in the Android SD I burned this evening.
EDIT: I was finally able to get Etcher to write the image, after switching from Ubuntu (dd succeeded but failed to boot) and running Etcher in OSX. It booted up late last night.
EDIT: I was finally able to get Etcher to write the image, after switching from Ubuntu (dd succeeded but failed to boot) and running Etcher in OSX. It booted up late last night.