Ask them to send you the reset microsd to restore to stock. They sell it separately, but why pay if they agree to send it to you for free. They won't put it online cause they say you don't know how to properly format the sd card and may brick the device if it is not formatted properly.
Link to the card in case you want to lose more money.
https://gromaudio.com/store/accessories ... -card.html
If you want to try yourself for free then download, extract, and copy the 3 files onto a microSD card. The card I received is 8GB formatted to FAT32.
TRY AT YOUR OWN RISK. I'M NOT RESPONSIBLE IF YOUR DEVICE GETS BRICKED.
- Reboot Into Recovery, wait for main screen with menu
- Insert SD card
- Click "Update to 8.1 from SD Card"
https://drive.google.com/file/d/1eB7kO4 ... sp=sharing