I upgraded my Spark to the latest firmware tonight using the Windows App to do so.  No when I turn on my Spark and try to connect my phone to it, it no longer shows in the list of wifi connections.
I use an Iphone SE and sometimes a Ipad Mini 4.  It does not show in either.  The RC controller shows fine and I can connect using it, but what happened to the spark wifi used by the phone when you don't want to use the RC?

You need to reset the AC wifi to relink it back to your phone.

Search the youtube for how to link the spark to the phone.

Hi, Chirp. Did you solve the problem? Please follow the following video and try again.