I assume you followed the instructions on the [wiki](http://www.orangepi.org/orangepiwiki/index.php/Orange_Pi_CM4#How_to_burn_a_Linux_image_to_eMMC_using_the_dd_command) to flash to eMMC using

dd

. did the eMMC show up when you ran

ls /dev/mmcblk*boot0 | cut -c1-12

to identify the eMMC device ID? it didn't show up on one of my CM4's when I first tried to flash it