Problem with coping mmcblk0 to pc
To copy mmcblk0 or any partition directly to pc, you need root access and busybox installed on your android phone.

Working ADB command is adb -d shell su -c busybox dd if=/dev/block/mmcblk0 bs=4096 &gt; D:\mmc.bin

Or try these following links
https://www.youtube.com/watch?v=aWgJdwn0-4M
https://www.youtube.com/watch?v=Qo5lBWAIb4g