I opened the official 1.6 that was in my m92 and I wonder if the actual upgrade steps are correct:
You can update the software by follow steps:
• Save the updates package in a SD card.
• Make sure the updates package is located at the root directory of the SD
card. The name should be ‘onyx_update.upd’.
• Insert the SD card into device.
• Restart device, press and hold the OK button. NOTE, the OK button should
be pressed before the device restarts. Hold it until you see the message
‘Software update request detected, checking updates…’
Device updates itself automatically. It restarts after update finishes.