Well I finally have my second Lightbridge ground unit working thanks to Gaucho's firmware flash fix. This was the standard video loss caused by  failed firmware in the ground unit. A common problem which DJI refuse to acknowledge. Total cost of  $5.79 for a  serial adaptor compared to $509 quote from DJI, I had the ground unit repaired in about an hour. It just shows how disgraceful DJI are when they fail to admit this problem is their fault through a design flaw and not the customers.

Glad to know the issue has been figured out, we are sincerely sorry for the unpleasant experience with our repair center, we listen to all the feedback on social media, your feedback will be forwarded to our engineers for attention, we will keep improving to provide you all more professional service.