If you’ve got the CLI working, try particle serial wifi that should let you manually enter credentials over serial. Mind you that you’d still have to claim it then. particle identify along with Particle device add [ID] should help with that.
Let me know if that worked for you.
Not sure if it’s related to the older firmware, but the new one does have some fixes in regards to stability, connection-wise as well. That’s the reason the automatic firmware updates are now available, as to enable pretty much anyone to conveniently update to a more recent version.