Corrupted or outdated drivers are a primary cause. Reinstall using the Rockchip Driver Assistant .
If Batch Tool keeps failing, try (often used for SD card flashing but supports USB burning too) or the older RKAndroidTool . rockchip batch tool loading firmware failed
The error message "Loading Firmware Failed" accompanied by the status "Solid Piece" (or sometimes showing a solid color bar in the UI) in usually indicates a communication break between the PC and the device during the flash process. Corrupted or outdated drivers are a primary cause