Hi10 XPro T606 - "your device is corrupt"

Serial Number: YH10XpAB50240103490

Bought from Amazon, about a year or so ago

Hello everyone, I turned off my tablet and, when I turned it back on, it displayed the message “your device is corrupt, it can’t be trusted and may not work properly!" and rebooted again and again.

I have searched through this forum, and it seems I need to flash the firmware, but I cannot find the firmware for my serial number. Any help is appreciated.