Solution: Corrupted download. Re-download the V2.1.0 file, verify checksum, and repeat. Also, try a different USB drive (older, smaller capacity drives work best).
Solution: The main firmware partition may have been erased or is incompatible with the new bootloader. Use the USB method to now flash the full system firmware (Android/Linux image) appropriate for V2.1.0. Stb Erom Upgrade V2.1.0
However, respect the process. Read the manual for your specific STB model. Use verified files. And never, ever interrupt the power during the upgrade. With caution and this guide, you will successfully transform your STB into a more responsive, secure, and versatile media hub. Solution: Corrupted download