If you're going to sell it, I wouldn't touch the software update mechanism at this point and maybe let the new buyer decide if they want it or not. there's no benefit to you to perform the update that I am aware of.
Potential buyers who know their DJI drones will always give first look to those carrying earlier firmware.
.790 may not be considered earlier firmware by many potential buyers. The next firmware release(.797)claims to involve the RID debacle. With the age of this product, doubtful DJI will release any additional updates.
If I managed to find a second hand mav.2 on .0670 firmware: I'd snap the sellers hand off. Last fully featured firmware on ARB#1 without all the subsequent "security fixes".
I'm going to look at a Mavic 2 pro with smart controller tomorrow for $300. Smart Controller is fine but he says Mavic flys fine but gimbal is "unsteady". . .still worth picking it up? What are you selling yours for and is any issues with it? Thanks 
That's what I thought. . I've been out of the loop on the latest on DJI drones. . was super into it then, after my Phantom went into a tree and it was "repaired". .it was never really quite the same. . I've flown here and there. . maybe a few times a year but haven't kept up. . Don't know much about the smart controller, Mavics, etc. but checked a couple Youtube vids on the smart controller, how it's brightness compares to a Crystal Sky standard, really nice controller to use, it won't work with either my Phantom or Spark. . if it came with a Mav 2, would it work with a Mav 3 if I can't get this 2 Pro to work correctly? Thanks for super fast reply and I'll be visiting this forum quite a bit if I do pick it up but judging from that response it's a no-brainer. . and thanks again
