What happened?
While flashing firmware to your printer an error might occur, and the screen will display the following message: "File system error! Try a different USB drive or format the drive with FAT32 filesystem (all data will be lost)".
Error name: File system error
Error code: #12613
The printer shows this error when it can't read the USB drive.
How to fix it?
Connect the USB drive to your computer and format it as shown here. After that, try flashing the firmware again.