Three times on my recent Iceland trip I had problems where the M2Z would either not connect to the controller or once up in the air the connection failed repeatedly. Looking at the photos and videos from those flights, most have a slightly blurred image.
Any thoughts?
Was it the controller or the phone connection. I had it twice where the controller was connected but the phone lost connection. In which case it could be the cable.
Blurred image, I’ve no idea sorry.
It was the phone dropping off that I noticed first, and my first thought was the cable, until I got home and saw the blurred pictures. Maybe just a coincidence.
The only times I’ve had blurry pics is when I forgot to AF once in the air. Looked fine on the small screen but at home in post production, it was clear I was out of focus 
.
Oh, and one time when the filter lens was cracked or smudged 
.
I’ve also had connection problems with a cheap cable. The one that came with the M2P broke after I rolled it up too tightly.
I use braided nylon cables and never had a problem, you might pay a little more for them but think they are worth it.
Replaced my cable and still had problems. Could be the controller connection port perhaps.
Have you tried using the bottom USB port to your device?
On my to-do list!
Short of there being another problem, I would think that may cure your disconnection problem.
I personally use the bottom port at every opportunity, the side port always looked crap to me, right from the first Mavic Pro produced.
My problem is intermittent: failed with brand new cable this morning; then worked on old cable; worked again fine this evening with the old cable, all using the side port. I need to get a cable of the right length to use the bottom port, I’ll try that some time soon.
I’d have thought any length of cable, even your phone charge cable would answer your question.
What difference does having the right length matter?.
All you are doing is trying to eliminating what the problem is.
I would just coil the phone charge cable up and put it behind the phone.
If it solves your problem, then buy one the length you want.
I can’t prove a negative - I’ll only know if the bottom port cable is the right solution if I try it multiple times and it never fails, given that the side port cable only fails occasionally. I’m not doing that with my big long phone charger cable, I’ll get something shorter if I’m going to be doing this repeatedly.