My first post.  My first DJI drone.  Wow... the Phantom 4 has already produced some of the best video I've even drone shot.  But then it has it's problems...  Short Version:  Using my son's iPad since it has LTE and I was flying a job that required map updates.  All went well (19 min flight) then brought it down for a battery change.  Then, persistent disconnect and reconnect.  Drone flys perfectly, but the DJI App no longer streams video and "disconnects" constantly.  Had to quit the job.  I believe I may have fixed this... and I don't work for DJI so take my solutions with a grain of salt...

1. RC (Remote Controller) FIRMWARE is only updated via the DJI GO app while attatched to a Mobile Device with an Internet Connection.  Open DJI App, upper right corner "..." opens a menu for the TOP ROW icons.  Scroll to bottom, look for another "..." and you'll see the VERSION of your APP, Phantom, Remote Controller (RC), and RC SERIAL NUMBER.  Check to make sure all the version are up to date.

[NOTE: if the RC version is called Unknown Version... then you are either not connected to the Phantom -or- an Update was aborted and it should be restarted.  Older Phantoms had a seperate RC Assistant... but the Phantom 4 does not.]

2. DJI Assisant 2 - The Phantom Firmware can be updated in two ways ... Via a connected RC/Mobile device (not preferred) and via a PC/MAC using the included cable.  First, download the App (Not Obvious on the website... scroll to bottom of Phantom 4 support page.  Be sure you get the PC or Mac Version).  Curiously, while called the "DJI Assistant 2" it installed on my Mac as simple "Assistant".  (Some have noted you need to install a DRIVER... but I didn't have to).  Sequence... plug Cable into the Phantom, Turn Phantom on... then Open the Assistant App.  Do not plug the USB in yet.  Make sure you're "LOGGED IN" to the App.  When all is good, then PLUG IN THE USB.  Follow the Prompts.

[NOTE:  If you decide to Update Firmware on the Phantom via the RC/MOBILE Internet... then you may need to first FORMAT YOUR SD CARD.  Why?  The Phantom doesn't have enough free memory to keep a FIRMWARE update in RAM... so it writes to the SD Card.  Other files/directories on the SD CARD, per others reports, can cause a failure.  So Format the card first.]

Some Users have found that the DJI Assistant 2 FIRMWARES don't take... the screen reports that the update worked but upon closing and rebooting the Phantom does not have an updated Firmware.  In these cases, "RESTORE TO FACTORY" then update to the new FIRMWARE.  (You may need to reset the RTH and other settings... I just don't know.)

3. DJI GO APP - Crazy as it sounds, I believe it was my "Logging In" to the DJI GO App was my downfall.  Why?  I have no idea.  When I got home, I deleted the DJI GO App, hard-rebooted the iPad, then Reinstalled.  Seems to link better.  Some have reported of using multiple iPads/iPhones can also cause linking problems... so if you fly with the same iPad all the time, then switch to your iPhone at the beach... you may have linking problems.  Delete/Download/Install DJI GO again.  Less problems.  Then again, once you DELETE/DOWNLOAD... you have to RESET MANY PARAMETERS on the App... I Wish there was a way to keep (entirely) different configuration settings that persisted across several devices...

4. RELINKING - Some have reported that RELINKING the drone to the RC Radio has helped.  Go to the "..." menu, look for RC icon, then choose LINKING REMOTE CONTROLLER... you'll need a Paperclip (small pin) to reset the connection.  Start up everything as normal.  Start the LINKING and a small red dot blinks on the Phantom near the SD Card slot.  Press the light with a small in and the link is re-established.   My signal strength increased slightly.  Slightly.

5. GIMBLE CALIBRATE - Has nothing to do with DISCONNECT, but when you add lenses to the Camera (ND or CPL filters) it's best to re-calibrate the gimble (once) before the first flight.  Under the DJI GO upper right screen "..." menu, look for CAMERA icon, and re-calibrate gimble.

6. SIGNAL BOOSTER - silly little device you can purchase from various sources which keeps the Antenna parallel and reflects Phatom's signals back to the Antenna.  Signal Strengh didn't change at all but the distance before my first dropout increased by 50%.  Does it work?  I dunno.  It was $16 shipped - I got the Copper one.  It was real copper... some have reported that eBay rip-offs show up with vinyl stickers printed to look like copper/gold.
7. iOS Hardware Decoding - Some have reported that ENABLE HARDWARE DECODING (upper right screen "..." menu, scroll to bottom and choose "..." to pick General Settings) completely messes up their display.  If you're having problems, turn this off.  Then again, if it's off, turn it on.

8. Older iPad Overheating - With our Without HARDWARE DECODING, the video-processing makes my older iPad Mini 2 heat like a frying pan... and the Green Screen comes back.

9.  Cheap 3rd Party Lightening Cables - I'm cheap... I get high-quality Apple-Rip-Offs for around $2 each... they charge nicely, but then you start to Sync or process a LOT of data, they poop out.  Be sure you try different cables, including an actual OEM Apple Lightening USB cable.

10. HEAT! HEAT! HEAT! HEAT! HEAT! - Constant disconnects happen more on 2nd/3rd batteries since the 1st battery is as hot as an oven... so is the inside of the bird... you could either cook some stuffing... or you could give the bird 10 minutes to cool down inside an ice-cold air conditioned car.  

[Note:  I could use some advice on keeping the whole system cool (under 37* Celcius)... when it's hot outside ... the bird cannot shed heat fast enough... and flights become very short.  Ideas?!?  Drill vent holes?  Get a custom Phan4 top?  Reflective coatings?  Icebags?  Dry Ice?  Alcohol rubdowns?]



SUMMARY:
A.  If you're using multiple Mobile Devices (iPhones/iPads/iPad Mini) to run DJI GO, see if the DISCONNECT occurs on all devices before anything radical.  Delete, cold restart the device, reinstall, try again.

B. If you end up needing a FIRMWARE update, use the DJI GO App to update the RC - and confirm it worked, then use DJI ASSISTANT 2 to update the Phantom, and if that fails, restore to Factory Settings and Re-Update the Firmware.

C. Keep the Bird Cool!

This had been frustrating but has kept me in the air getting excellent video.  GO PHANTOM 4!!!

Any ideas on keeping the Phantom 4 cool?