Mostly,, lsblk to be sure of number,,, mmcblkX (emmc is device with boot[1,2] sections on it)
Also, before zeroing save mbr (or take note of sector numbers)
(you can run fdisk on an image, for various reasons)
dd if=/dev/mmcblk2 of=emmc.mbr count=1 (obviously in dir where save is wanted)
Then, after zero restore mbr,,, dd if=emmc.mbr of=/dev/mmcblk2
(or run fdisk, plugging in noted sector numbers)
If you don't have a mbr you can't access emmc (except as a 'raw' device)
(well, you can do a manual mount with -o loop,offset=<BYTES> or ((512*SECTORS)) ...)
Also, before zeroing save mbr (or take note of sector numbers)
(you can run fdisk on an image, for various reasons)
dd if=/dev/mmcblk2 of=emmc.mbr count=1 (obviously in dir where save is wanted)
Then, after zero restore mbr,,, dd if=emmc.mbr of=/dev/mmcblk2
(or run fdisk, plugging in noted sector numbers)
If you don't have a mbr you can't access emmc (except as a 'raw' device)
(well, you can do a manual mount with -o loop,offset=<BYTES> or ((512*SECTORS)) ...)