Hi mbrusa,
When I downloaded the link from your signature line for the TSDZ2-v20.1C.4-2-860C.hex file it has a size of 60.1kb. When I download it from here: TSDZ2-Smart-EBike-860C/releases/v20.1C.4-2-860C at master · emmebrusa/TSDZ2-Smart-EBike-860C, it's 468kb. I think the 60.1kb file is...