@Celsian If you formatted the card before it did the update - I would take the card out and double check what you actually have on the card.
The steps to return to stock should be as simple as:
- Reformat your card in fat32
- Download latest firmware from BV site
- Copy all folders to the SD card - including the BV folder itself - this is important!! (So you card will look like this for example: F:/Blackvue/Config) where F is the card, and I used the config folder purely to show it's under the main BV folder.
- Insert in camera and switch on.
- At this point mine did give me a problem, so I left the card in the camera and cycled the power - it then picked up the firmware and updated.
If your updates are failing, then I would suspect either step 1 or 3 were not done correctly.