Nextbook has a history of changing internal hardware without changing product names. You are strongly advised to review your stock build.prop entries to verify compatibility before flashing. The easiest way for most users to do this is to download any build.prop editor app from the Play Store.
The red portions of the following build.prop entries should match to ensure compatibility:
ro.product.model=NX785QC8G
ro.product.name=M865FD
ro.product.device=NXM865FD
ro.build.product=NXM865FD_WMDE
ro.build.description=NXM865FD_WMDE-user 4.4.2 KOT49H V2.0.9 release-keys
ro.build.fingerprint=Nextbook/M865FD/NXM865FD:4.4.2/KOT49H/V2.0.9:user/release-keys
ro.product.usbfactory=NX785QC8G
If one of the above values doesn't match, or you are unsure about anything, you should post a reply in the support thread and ask for advice before flashing.
After installation, I recommend using the backup feature of TWRP to create a full backup of every partition on your device. Then copy this backup to a PC for safe keeping.
Installation Options:
From stock recovery:
1. Verify compatibility as indicated above.
2. Download this file: SMT-NX785QC8G-NXM865FD_WMDE-TWRP_rkimage.zip
3. Unzip the file.
4. Extract update.img
5. Put update.img on external SD card
6. Flash update.img using the install from rkimage feature in stock recovery.
From TWRP/CWM etc:
1. Verify compatibility as indicated above.
2. Download this file: SMT-NX785QC8G-NXM865FD_WMDE-TWRP_Recovery.zip
3. Put the unopened .zip file on your external SD card.
4. Flash using TWRP/CWM recovery.
Removal Instructions (Return to Stock Recovery):
1. Verify compatibility as indicated above.
2. Download this file: SMT-NX785QC8G-NXM865FD_WMDE-Stock_Recovery.zip
3. Put the unopened .zip file on your external SD card.
4. Flash using TWRP/CWM recovery.
Support Thread:
ShaunMT-s-TWRP-Recovery-For-The-Nextbook-NX785QC8G-NXM865FD_WMDE-(Support-Thread)