Mac OS X Ubiquiti AREDN Initial Firmware Installation. I need help loading the AREDN firmware onto my Powerbeam with my Mac.

I personally prefer using Ubuntu 18.04 for all of this AREDN stuff. But, when I use my Mac to flash Ubiquiti nodes I use an app called 'PumpKIN'. It is a GUI-based TFTP tool that simplifies loading firmware. See the photo I have attached. I think you can ignore the 'PumpKIN Preferences' window and just hit the "Put file" icon on the main 'PumpKIN' window. When the 'Put file to remote TFTP server' window pops up, just fill out the remote host, port, and other info with what you see in my photo. Hit the "Browse" button and select the appropriate 'aredn- xxx.bin' file for your correct Ubiquiti node and then hit the "Start transfer" button and another window will pop up showing you the progress. Make sure you've selected the proper Ubiquiti file and pay close attention to whether your device is XM or XW hardware (if appropriate). 
When this completes loading just browse to the AREDN 'NOCALL' address to begin configuring your node. 

-Damon K9CQB