I have tried using an external antenna, no luck there, an external USB wifi adapter, no driver available. I have tried setting my 15 year old router to offer completely insecure wifi, the O2+ still can't connect to it. I have tried using my cell phone as an access point, both secure and completely insecure, still no luck.
I am afraid that my inevitable conclusion is that this whole project is garbage, if not a total scam. I will try to get the reseller to accept a return for a total refund.
My 15 year old router, a Netgear WGT634U, has been running OpenWRT for many years now, and I have compiled the image from scratch more times than I care to remember, so this is not related to lack of knowledge or experience.