I’m fairly new to droning. Had a few cheaper ones. Decided to buy a Phantom 4 pro refurbished one from a DJI dealer on Amazon. Got the drone in its case and everything looks brand new. All stickers and plastic on RC and drone. Package like a new one I’m assuming. Charged everything up and plugged my IPhone 12 with no success. I could fly drone with RC in the beginners mode but no video. Read all kind of forums and watched videos. DJI support said DJI GO 4 didn’t support IPhone 12. Tried wife’s Samsung pad and a Samsung go phone. Nothing worked. Went look at IPads because they were capable. Tested it out. Nothing. Went to my friends house that’s computer savvy. He look up everything he could online, plugged his phone in. Downloaded DJI assist 2 to his computer. Didn’t know that. Updated drone. Couldn’t update RC. Only on DJI go 4. But couldn’t connect. I had my bosses old DJI phantom 3 remote in my truck. It was broken. Decided to try it. Plugged phone in and wouldn’t connect with drone, but phone connection was a success. Long story short, we swapped out the USP port from old RC to new RC and it worked. The board is bad. Tries both ports and nothing. Downloaded software and flew for the first time with camera. Awesome. Hope this can help someone.