Download Vernee M6 official stock firmware from the link in this post and follow the provided flashing instructions to learn how to flash. This firmware is an SDcard package, to be flashed via stock recovery. So, you basically need just an sdcard and your device to flash the firmware.
If you notice that any of the links provided below is broken or doesn’t work, please post in comments section so we fix and update it ASAP.
How to flash
1. Download the ROM file from above link and copy to your device internal storage (sdcard).
2. Launch “Setting” -> “About Phone”->“wireless update”, then click the icon at the top right corner, and choose “Local updates”;
3. Click into “internal storage”, find the ROM file and choose it;
4. Click “install now” and choose “OK” from the popup to commence update.
5. Wait patiently for the flashing process to commence and complete. During this period, your device will reboot. That’s all.