Recently my best friend installed some unifi access points in his home. We had ordered a 60W unifi switch, a couple of AP-LR, and a couple of AC-Lites. These were ordered and sat for several months until we could get around to installing them. Upon installation, the AC Lites were adopted and had to go through the normal upgrades to bring them up to the latest version.
However, the AP-LRs were used and had very old firmware on them and would not upgrade properly. They would adopt but not upgrade. We fixed this in the following ways.
1. We Factory reset the APs. At this point, they grabbed DHCP from the local network. Quick ssh into the AP verified it had internet connectivity.
2. I was able to find some old firmware on the UBNT web-site. We issued the following command to each LR AP
the “HTTP” is important to note. If you copy the link directly from the UBNT website it has https in it. The older firmware blows an error due to invalid certs (fixed in newer versions).
Once it came back we were able to upgrade from the controller.