Wed, 15 Apr 2026 06:22:51 +0000

Want to protect the boot sequence and the kernel command line in U-Boot to make your embedded Linux device harder to hijack?

The good news is that U-Boot lets you make specific variables read-only.

Here's what I learned using the CONFIG_ENV_WRITEABLE_LIST configuration option in U-Boot, on my project with a Toradex SoM.

I followed a tip from Ayoub Zaki on last-week's post on accessing the U-Boot environment from a C program (https://rootcommit.com/2026/accessing-u-boot-env-from-c/).