Switch 5 Puertos Gigabit Ubiquiti Unifi, Admin L2, Desktop, PoE-IN 802.3af/at, USB Tipo-C Power IN 5V 1A.

To managed and to adopt, must upgrade the USW-Flex-Mini switches.

It took a lot of troubleshooting, but I eventually got it working.

To preface this, I initially thought the issue was my controller. As someone in the thread stated, the controller needs to be at least 5.12.5 according to the USWFM documentation. I was at 5.12.35, so I upgraded to 5.12.6.

This controller is in AWS, so it is remote. I wasted A LOT of time on the local controller I spun up as a last resort. To be fair, it seemed to work for other users. I would always get the "Adopting" and then "Disconnected" notices after trying.

And to echo other complaints: NEVER found the devices via Ubiquiti Discovery in two different Windows 10 machines, nor could I find it in the iOS app.

The USW-Flex-Minis were all at FW 1.6.1.525 (October 2019, I think) out of the box.

Here is what worked for me, in the end on 2 of the 3 devices.

1. Create a Corporate LAN in your site - 192.168.1.1/24, assuming you do not have one
2. Connect an Ethernet cable to your main switch - note the port number. This will go to the USW-Flex-Mini, later
3. In the controller, set the switch port group to the 192.168.1.1/24 network you created
4. On the bottom of your USW-Flex-Mini, hold the RESET button and attach the power - keep holding the RESET button until the switch enters recovery mode - blinking white & blue LED on the front
5. Now connect the Ethernet cable
6. You should see the switch pop into your controller and it can now be adopted

I should note that I was able to connect 2 of 3 switches ONLY by entering recovery mode.

Another switch connected straight out of the box to the 192.168.1.1/24 switch port.

Also, I could never get the default web server with fwupdate.bin to upgrade. I don't know if that's an issue with the FW or some oddity in my network after 3 hours of screwing around.

http://192.168.1.99/fwupdate.bin never seemed to matter in all of this.

USW Flex Mini adoption issues | Ubiquiti Community