can't add Phantom I Golds after upgrade to DOS 2.0

[JDtheJD]

I upgraded two Phantom I Golds to DOS 2.0, and now I'm unable to "add product" them using wifi.  I am able to add them via ethernet, but I don't have ethernet connections convenient to where they will ultimately live, so that's not a long-term solution.  Both worked via wifi before the upgrade.  Also, once they're set up via ethernet, I can find no way of adding wifi info after the fact.

The only reference I've found to the issue is this thread, where the user got no solution from Devialet support after several weeks, and eventually the problem just went away after a subsequent system update & reinstall of the Devialet app.  But I've tried everything he listed, and both speakers are running the latest update.  I also upgraded the associated Dialog, which didn't help at all.

I've done the following multiple times:  the three-click "setup mode", the long-press reset, power cycle, and reinstalling the app.  I've tried both iOS and Android versions of the app, as well.  (I found that the Android version wasn't even able to locate and add them via ethernet reliably, but the iOS app could, though it sometimes needed to be reinstalled.)  

Is there some secret sauce to getting Phantom I's to connect via wifi under DOS 2.0?

I avoided updating to DOS 2.0 until I bought the new remote which only works with the DOS 2.0.  I had lots of issues for an extended period of time, but I Devialet support was very responsive; not always immediately successful, but always responsive so I recommend going down that route.  

That said, here are various things I done: unplugged for several days, rebooted routers, bought a new Ethernet switch, router, and cables.  I think I also manually designated my Phantoms to use Wi-Fi vice PLC (did the opposite too) and went through several iterations of updates.  

At the moment things seem fairly stable. I had varying degrees of success with the above.  I suspect there is a “secret sauce” but unfortunately it is inconsistent to such an extent that what works for me may not work for you.  If you discover it, please do share.