Let me start with these questions for forum members:
1. Is anyone successfully using a Samsung S6, 7 or 8 that has been upgraded to Nougat?
2. Anyone who has had similar connection problems with Samsung S6, 7 or 8 that has sent in their Mavic and or RC, was the connection issue fixed?
3. After reading below, does anyone have any suggestions for steps I may have missed?
4. Is the only solution to purchase an iPhone or iPad assuming these work well with the latest Mavic updates?

First a Repair History timeline:
1.        Mavic Pro sent for repair April 7th
2.        UPS tracking showed it arrived April 11th
3.        Case accepted April 17th
4.        Received (whatever this means) and Damage Assessed April 28th
5.        PayPal payment made immediately as PayPal account shows:
"Payment sent to IFLIGHT TECHNOLOGY COMPANY LIMITED April 28, 2017 at 9:48:56 AM PDT."
6.        DJI received payment 4 days later May 2nd.
7.        Received call from DJI North America May 8th and follow up email says:
"Your case was escalated and your shipping was upgraded from standard to 2 day." Whoopee!!!
8.        Next we see DJI's timeline says Product Delivered May 12th.
9.        Wait a minute (or 6 weeks), on May 11th, I received Shipped notice with UPS Standard (5 day).
10.        Unit finally arrived May 18th.
Even with DJI Care Refresh, frankly, the 6 week turnaround was not surprising based on other's experiences.

Some background, I have a Master's Degree and since 1984 have had 3 successful Computer businesses. I think I understand reading manuals and directions. Also know the value of peer to peer help and read forums regularly.

After receiving the repaired or replaced Mavic 3 days ago, I've spent at least 20 hours trying to connect the RC using my Samsung S6 to the Mavic. The S6 previously worked fine with the Mavic. The S6 was updated to Nougat whilst Mavic was taking vacation at Cerritos repair center.

The returned Mavic came with version 4.0.700 firmware. First 8 hours spent trying to get RC (not sent in with repair) to upgrade to 4.0.700. Tried updating through latest DJI Assistant 2 as well as unsuccessfully through RC. Finally downgraded Mavic to 4.0.400 and was able to connect RC to Assistant 2. Next, Upgraded both RC and Mavic to 4.0.700.

Then received messages like, "Failed to send commands, try later," and Failed to save (device name)." DJI Go4 at bottom of first screen says, "RC Connected." Main screen says, "Aircraft Disconnected."

Tried myriad suggestions from Forums. Things like using the lower USB port without the small connector connected, turned off Wi-Fi, tried connecting RC to Mavic with the Wi-Fi feature. The last, after some difficulty, led me through  to register the Mavic. I felt that must have fixed the problem. No such luck. Thought of Dante's words, "Abandon hope all ye who enter here." I GIVE UP.

Marty Markoe, a beaten man

“Hold fast to dreams,
For if dreams die
Life is a broken-winged bird,
That cannot fly.”

Don't give up hope yet, I think you need the help of a moderator, you can PM one of them if you choose, and I'm sure they will contact you and offer some help.
I could tell you this and that but I'm sure you've been through most of what I would tell you.
So hang on just a little longer. Good luck..

I would get the assistant 2 working, that's the key before do anything else. Reset the defaults then refresh the firmware on both. Might as well uninstall go 4 too, delete the cache and manually delete the dji folders, reinstall it. That's starting from scratch. If that doesn't do it, least you narrowed it down. It could be nougat related too. Maybe downgrade to android 6.

thehippoz Posted at 2017-5-21 11:23
I would get the assistant 2 working, that's the key before do anything else. Reset the defaults then refresh the firmware on both. Might as well uninstall go 4 too, delete the cache and manually delete the dji folders, reinstall it. That's starting from scratch. If that doesn't do it, least you narrowed it down. It could be nougat related too. Maybe downgrade to android 6.

Glad you mentioned Assistant 2. That is what I finally got to work. What did the trick for me in Windows 10 was to right click the program icon and click, "Run as administrator." However, that just allowed me to upgrade and then downgrade RC and Mavic.
Marty

Did you re-pair the RC to the replacement?  The RC has to be relinked, it's not automatic.

eyecapture Posted at 2017-5-21 16:32
Did you re-pair the RC to the replacement?  The RC has to be relinked, it's not automatic.

I'll be a monkey's uncle. I'd tried that several times before and there was no choice to hit OK and proceed. Figured what the heck and tried it again. There was the OK choice and the RC/Mavic linked. All appears to be working well. Will try to fly tomorrow.
Thank you,
Marty

Marty, thanks for sharing your experience with us here, sincerely sorry to have kept you waiting to get the drone back from repair center, we're working very hard to speed up the process recently to get everything sorted out as soon as possible.
We are glad to hear you managed to upgrade both aircraft and RC through Assistant 2 successfully and figured out how to get them linked finally.
Hope you enjoy the time on flying!
Should you have any further questions, please feel free to contact us, we'd love to help.

DJI Natalia Posted at 2017-5-22 00:34
Marty, thanks for sharing your experience with us here, sincerely sorry to have kept you waiting to get the drone back from repair center, we're working very hard to speed up the process recently to get everything sorted out as soon as possible.
We are glad to hear you managed to upgrade both aircraft and RC through Assistant 2 successfully and figured out how to get them linked finally.
Hope you enjoy the time on flying!

Thanks for your concern. I was wondering if it is possible to get an extension on the DJI Care Refresh Service Agreement considering the long delay and lack of coordination between support group and repair group? If you think you can do this I can PM my Care Refresh #.
Thanks,
Marty

Marty Markoe Posted at 2017-5-22 05:59
Thanks for your concern. I was wondering if it is possible to get an extension on the DJI Care Refresh Service Agreement considering the long delay and lack of coordination between support group and repair group? If you think you can do this I can PM my Care Refresh #.
Thanks,
Marty

Sorry I did not receive your message, could you please try to PM me again? PM does not function properly sometimes.