I am working on an IoT app in which there is an on boarding process where the user connects to an access point, which has not internet connectivity, configure the device and the
I had the same issue. What I did is adding a step to the boarding process where I invite the user to go to there settings, add manually this network with no data and accept the popup shown by the system.
I have not found a real solution yet. However, I've seen an app called eWeLink where they manage to do it, but it is not an open source project.