So after a bit of work I got Sierra installed on to my MacBook Air 2,1! The only issue is wifi. To remedy this issue till I can get a new wifi card, I decided to see if I could use my Linksys AE6000 on Sierra.
Linksys AE6000(or similar RT2870 card)
Yosemite RT2870 kext
D-Link Pref Pane(DWA-140, thanks! @rodrigocunha)
To get the Yosemite kext for the RT2870, I had to go through Mediatek's installer with Pacifist. I did try the Mavericks kext from the other RT2870 thread but it didn't work.
The files will be attached below! (RT2870 Kext,DWA-140 Pref Pane file,Kext Utility
Now to the process:
I'm not sure if order matters but I had the DWA-140 Pane installed already Next drag and drop the RT2870 USB WiFi in to Kext Utility Reboot(with or without your USB Adapter attached) Your adapter should be blinking or working with the DWA-140 Utility
Have fun, enjoy!
This is a new updated kext and utility directly from MediaTek for the MT7610U and MT7612U network chipset.
This utility was updated and released on January 20th 2016 on MediaTek website.
I have the Netgear A6210 AC1200-WiFi USB 3.0 Adapter and it works perfectly under OSX 10.11.2 with USB 3.0 and 5GHz networks being recognized.
It should work for any card with one of those two chips.
I have had some serious trouble updating my system to macOS 10.12 Sierra but I have finally seemed to have gotten it working. When I have done a clean install and installing this package afterwards, It didn't seem to work. However after updating a working copy of El Capitan to Sierra with this package already installed, it seems to work.
So as of this post, this same package does work under macOS 10.12 Sierra but you might have some trouble like I have until mediatek performs their own official update.
I have finally figured out what is going on with this installer package. When you run this package as is, it will not install the kext on macOS sierra. It will install the wireless utility and all associated files but not the actual kext. I have included the kext as a standalone as well.
Install the Kext with kext utility then run the installer pkg. Reboot and you will have a perfectly working USB wireless stick.