As an aside - earlier this week I was able turn it on, connect to it, and manage through the brck cloud using a wifi bridge. But it was unstable, and I also couldn't get the SIM to work. When I came back to it, I couldn't get the SSID to show up. I've rebooted it and also tried a reset (holding the power button down for 15 seconds - red light flashes; it turns off; I plug in the USB power and it boots back up). Still isn't showing a the SSID.
Tried the installing the firmware file I found above per the instructions (unzip to a thumb drive, etc)... no red light appeared after inserting the thumb drive per the instructions, no change after 15 minutes and reboot. Unsure of next steps.
Edit: spoke to soon (like 10 seconds too soon). SSID just showed up and is reset, so apparently the firmware updated. I'll let you know if I get the SIM up and running.