I have successfully upgraded my device now to the Nougat version using the SD CARD method.
I did not have to do anything to enter "UPGRADE MODE".
@gcvanasel try to follow these steps, they might work for you
- Plugin your sdcard into some sdcard reader to your pc
- Open the Burn Card Maker program
- Check the "To partition and format", choose the correct image and press make.
- Plugin the SD Card into the vim khadas and plug in HDMI
- Power up and it should start to upgrade automatically (because your eMMC is erased)
This does not answer why I was unable to enter "UPGRADE MODE" using the other methods such as "Press and hold power, press reset and release power after a few seconds", MRegister Mode(Maskrom Mode), or erasing the eMMC.
I will try to see if USB Upgrade tool can detect my khadas tomorrow again.