We have used the most recent beagleboard debian eMMC flasher image to flash the beagle bone black eMMC. As of this writing: wget http://debian.beagleboard.org/images/BBB-eMMC-flasher-debian-7.5-2014-05-14-2gb.img.xz
After flashing is complete, erase the sd card, then reboot. Once booted, We can use fdisk -l to list our available devices, I found mine by checking the size and the partition table.
After verfifying the card's address, we can reformat it to fit our needs. Of course, this can be done before plugging the card in, as well.
debian@beaglebone:~$ fdisk -l
Disk /dev/mmcblk0: 15.9 GB, 15931539456 bytes
Device Boot Start End Blocks Id System
/dev/mmcblk0p1 8192 31116287 15554048 b W95 FAT32
After re-partitioning, it should look like this:
Device Boot Start End Blocks Id System
/dev/mmcblk0p1 2048 20973567 10485760 83 Linux
/dev/mmcblk0p2 20973568 31116287 5071360 83 Linux
From here we format the partitions as ext4 for the file system:
mkfs.ext4 /dev/mmcblk0p1
mkfs.ext4 /dev/mmcblk0p2
Next, we make a place to temporarily store the files from our rootfs
mkdir /tmp/usr && mkdir /tmp/home
and then we mount the new partitions we made to the appropriate points and rsync the data. If you have a new installation, this should be relatively painless, but it might take longer if you have a lot of files in these directories
mount /dev/mmcblk0p1 /tmp/usr && mount /dev/mmcblk0p2 /tmp/home
rsync -ahv --progress /usr/ /tmp/usr/
rsync -ahv --progress /home/ /tmp/home/
The last thing we have to do is alter fstab to reflect the changes we have made and the new location of our file system.
echo UUID=$(lsblk -no UUID /dev/mmcblk0p1) /usr ext4 defaults 0 1 >> /etc/fstab
echo UUID=$(lsblk -no UUID /dev/mmcblk0p2) /home ext4 defaults 0 1 >> /etc/fstab
After rebooting, we can check it like this:
debian@beaglebone:/$ df -h
Filesystem Size Used Avail Use% Mounted on
rootfs 1.7G 1.4G 236M 86% /
udev 10M 0 10M 0% /dev
tmpfs 100M 564K 99M 1% /run
/dev/disk/by-uuid/e2ab0b3b-9ad4-4fdb-97a9-830a9a2cba3e 1.7G 1.4G 236M 86% /
tmpfs 249M 0 249M 0% /dev/shm
tmpfs 249M 0 249M 0% /sys/fs/cgroup
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 100M 0 100M 0% /run/user
/dev/mmcblk1p1 96M 72M 25M 75% /boot/uboot
/dev/mmcblk0p1 9.8G 1.1G 8.2G 12% /usr
/dev/mmcblk0p2 4.7G 9.7M 4.4G 1% /home
Now that we see everything is as we expected, it's time to clean up the mess:
rm -r /tmp/{usr,home};mkdir /tmp/rootfs; mount --bind / /tmp/rootfs
Next, we simply add a test file to check if the mounting is sound:
touch /tmp/rootfs/usr/test
root@beaglebone:/# ls /tmp/rootfs/usr/
bin games include lib local sbin share src test
root@beaglebone:/# ls /usr/
bin games include lib local lost+found sbin share src
Everything works! We can finalize our changes and move on with our lives:
rm -rf /tmp/rootfs/{usr,home}/*