I recently downloaded the Jetson Nano 2GB Developer Kit SD Card Image version 4.6 from the Jetson Downlaod Center (Jetson Download Center | NVIDIA Developer). It says the MD5 sum should be dda5756b7e3897fddfe155fe50cf0b48, but the downloaded ZIP file has MD5 sum eff97e91a4631b7d0ebc366e66e75239. I’ve downloaded several times with same results.