This guide will show how to mount, read from, and write to the phyCORE-i.MX7 onboard eMMC. In order to follow this guide your phyBOARD-i.MX7 development kit must be booting from SD Card.
Be careful with the fdisk command. You can accidentally delete the contents of other memory devices connected to the system.
Step-by-Step Guide
Viewing available eMMC partition information
The eMMC corresponds to /dev/mmcblk2 in Linux when booting from SD Card. You can verify the eMMC partitions by using the following command:
Target (Linux)
fdisk -l
CODE
The fdisk command line utility will output disk partition information. Search through the list and verify the eMMC is listed. You should find an entry similar to the following:
Expected Output
Disk /dev/mmcblk2: 3.6 GiB, 3850371072 bytes, 7520256 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x243d4084
Device Boot Start End Sectors Size Id Type
/dev/mmcblk2p1 4096 20479 16384 8M 83 Linux
/dev/mmcblk2p2 20480 7520255 7499776 3.6G 83 Linux
CODE
Mounting the eMMC
In order to read and write to the eMMC you will need to create a directory and then mount the partition you want to read from to that directory. Follow the steps below to mount partition 1 of the eMMC:
Target (Linux)
mkdir temp && mount /dev/mmcblk2p1 temp/
CODE
Check the contents of the eMMC by entering the following:
Target (Linux)
ls temp
CODE
Writing to the eMMC
You can write to the eMMC by using the copy or move commands just like in Linux. To demonstrate, first create a test file.
Target (Linux)
echo "Hello World" > test.txt
CODE
Now copy this file to the mounted eMMC:
Target (Linux)
cp test.txt temp/
CODE
Verify that the file was written to the eMMC (test.txt should be listed in the output):