5.x software version is for 5.x hardware only, please do not upgrade if you are using 4.x software version.
5.x hardware: CPU is changed from x1021 to x1600, because x1021 is EOL.
Notes:
For x1600e, burn the files in usb_cloner_fw_5.1_5.1.zip with default configuration.
For x1600, you need to add mbrush_32m.cfg configuration to the burn tool, and then use this configuration to burn the u-boot_32m_350.bin file, and the rest of the burn files are the same as usb_cloner_fw_5.1_5.1.zip.