How to disable the option of booting from SD card in BBB

Question

I have a BBB running on angstrom. I want to increase the storage space, for that purpose I am using an SD card. The problem here is the angstrom images tries to boot from SD card if there is an card available on the slot and gets hang there as I am using that card only for storage purpose.

So how can I change the behavior of booting, or how can I disable the option of booting from SD card so that I can keep an SD card in the slot at boot time and boot BBB always from the emmc image. Main objective is to boot bbb from emmc image even if there is an SD card present in the SD slot

Answer 1

That sounds like a very very old U-Boot and thus probably also very old Ångström. Personally I'd upgrade that (as that also happens to get rid of what you are experiencing).

If you want to stick to the current setup, you'll have to figure out how to change the U-Boot environment variables to always point to the right storage device, or check if updating U-Boot would help.

One way, which is specific to your question and setup, would be to change the device name referred to in the environment. (If you insert a SD-card, it becomes the first device instead of the eMMC) You can probably find hints on the eLinux Wiki, but keep in mind that your U-Boot is ooold.

Answer 2

For this you just need to have a uEnv.txt in SD card to stop BBB booting from SD card even if it is plugged at boot time. The content of uEnv.txt should be, make sure to write this file in linux Env.

mmcdev=1
bootpart=1:2
mmcroot=/dev/mmcblk1p2 ro
optargs=quiet