If you have a device that you've tried to set-inform from SSH, but it's not showing up for adoption in your UniFi controller, a common problem is that the device's firmware needs to be manually upgraded before it can be adopted.
There are several ways to upgrade the device firmware locally, but the easiest way is to use the "upgrade http://<link to latest firmware>" SSH command.
First, you'll need to find the latest firmware available for your specific device model on Ubiquiti's downloads page. To find your device model, you can look on the back of the device or issue the "info" command in SSH.
For this example, we will be upgrading a UAP-AC-LR. We found the firmware download page for it here:
Under Firmware, click the download icon in the right corner of the top row to download the latest firmware version.
Click the "I Accept" button to accept the EULA.
Click the "Copy URL" button. No need to "Download File". We only need the link for the upgrade.
Now from the SSH prompt for the UAP-AC-LR, you can issue the upgrade command:
The device should reboot with the new firmware version which you can verify with the info command. Then you should be able to set-inform from there, or set-default then set-inform if you have any problems.