If you are looking for the correct way to handle a firmware upgrade for Ubiquiti hardware or searching for a specific document related to it, here is the relevant information: Official Download Sources
If you tell me the exact Ubiquiti model (e.g., LiteBeam AC, NanoStation M5, EdgeRouter X, UniFi AP‑AC‑LR) I will provide model‑specific commands and exact file name/paths and a tailored recovery procedure. Upgrade Firmware Version 1.255 Ubnt Download UPD