LED behaves differently and the first 2 LED cannot be disabled.
While this firmware can be applied to other models running airOS, UniFi cannot manage them and such action may void your warranty.
If you have a unit with a newer date code, i.e. 1336G, it may get stuck after the above upgrade. Symptoms are typically that the 3rd LED from the top (amber) will flash and it will not show up in DHCP table, by discovery tool or in the controller. To solve this please flash the firmware.bin file found in unifi_base/dl/firmware/BZ2/version/firmware.bin via TFTP soft recovery. For example, on Linux mine is found here: /usr/lib/unifi/dl/firmware/BZ2/18.104.22.1685/fi