I would like to connect to a 5GHz wifi with my broadcom wireless adapter [14e4:43a0] (Ubuntu 18.04 LTS). I feel like I tried all the options google had for me. At some point I had the wifi working for 2.4GHz in one session but after rebooting it was gone. I am beginning to doubt that this is achievable.
There is a current bug with the driver that make 5Ghz channels above 48 inoperable so lock your router to one of the channels 48 and below. My router will not connect with channel width other than 20 or 40Mhz so don't go locking yours to 80 or something and hoping it'll connect. I also stick to wireless N only on the router as AC seems to have some issues too. All things considered I'm ok with the results: 153554b96e