SD card issue with beaglebone black


I tried using microSD card as extra storage for my beaglebone black. I followed the steps as mentioned at

I was able to use mount microSD card successfully. However I am facing some strange issue.

when I do ls -lart on the mounted drive the permissions are

drwx------ 5 root root 16384 Jan 1 1970 drive

If I try chmod o+rx,g+rx /media/drive, to change the permissions, it does not work. No error on issuing chmod command but permission does not get change.

Infact I am not even able to change the user permission for any executable file under directory ‘drive’.

For ex.

bash-4.2# ls -lart /media/drive/jdk1.7.0_60/bin/java
-rw-r–r-- 1 root root 5822 May 7 20:26 /media/drive/jdk1.7.0_60/bin/java

bash-4.2# chmod u+x /media/drive/jdk1.7.0_60/bin/java

bash-4.2# ls -lart /media/drive/jdk1.7.0_60/bin/java
-rw-r–r-- 1 root root 5822 May 7 20:26 /media/drive/jdk1.7.0_60/bin/java

Since ‘x’ permission is missing, I am not able to execute any binary file. I am logged in as root user only. The jdk directory is expanded from jdk installer zip using command
tar -xvf Downloads/jdk-7u60-linux-arm-vfp-sflt --owner root --group root --no-same-owner.

No issues are encountered if the jdk directory is expanded under home directory instead of SD card.

The partition details for SD Card:

Usage : Filesystem
Partition type: W95 FAT16 (LBA) (0x0e)
Type: FAT (16-bit version)
Device: /device/mmcblk1p1
Mount Point: Mounted at /media/drive

Any help will be really appreciated.

Sanjay Ahuja

re-partition it as "ext4"... fat16 doesnt' support user permissions..


Hi Robert,

Do you have any pointer to steps for partitioning it as ext4. The link I followed specifically mentioned that partition type must be ‘FAT’. The content of uEnv.txt as provided there is

mmcroot=/dev/mmcblk1p2 ro

Would it remain same if partition type is ‘ext4’ or some values would change?

Basically what should be content of uEnv.txt if we are mounting external SD card with partition type ‘ext4’?

sanjay, uEnv.txt should not have to change at all, content wise. Everything in this file just “tells” uboot where:

  1. to load the kernel, and board file for the BBB

  2. where the root file system is.

  3. Lastly, optargs=quite means to be less verbose with kernel debug output ( I believe )