Even with a clean version like FlashTool-V5.8.41.0, issues arise. Here are fixes for frequent errors.
Using firmware that does not exactly match your device's model and hardware specifications can result in a total device failure. Corruption: FlashTool-V5.8.41.0-ROMProvider.COM.zip
Launch Flash_tool.exe and load the appropriate Scatter-loading file from the firmware folder. Even with a clean version like FlashTool-V5