Beaglebone Black: How to disable booting from a microSD?

Question

I need to prevent access to some files in eMMC. If I boot from uSD I can mount the eMMC and access the files, even if this files are protected with chmod 700 (where the owner is root). I thought several things to avoid this:

1. Disable booting from the microSD.
2. Encrypt somehow these files (it's a python API and some scripts in bash)

I think the first option is the best, if possible to do, but I don't know how.

After researching I saw that u-boot is used for booting, so I wonder if there is any way to configure it for disabling booting from micro SD.

Answer 1

It should be possible. Read chapter 5.3.5 - Boot Modes in the BBB_SRM BBB_SRM

Default it should boot from the internal eMMC. If you press the boot_button while plug the BBB on power it should boot from external SD-Card. So it stands in the BBB reference manual.