It would be nicer to disable the button rather than set a flag.

Also, on Tarako we'd display a spinner at this point because the rotation operation might take some time. If this code is ever actually needed (i.e. if this version of the camera every has to run on low-end hardware) then presumably there will be a UX need for a spinner here again. So if we're going to do this, I think you should have some kind of placeholder module with Spinner.show() and Spinner.hide() methods.  They don't have to do anything, but if you insert calls in the right places now, then it would be easy to add spinner feedback if it was needed later. And of course, there could be another build-time config option to say whether spinners should be displayed or not.