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Root Filesystem Protection and Integrity Issues
The kernel boot failure you’re experiencing after modifying files in the root filesystem is likely related to root filesystem protection mechanisms in Torizon OS. Let me explain what’s happening and why.
Understanding Torizon OS Root Filesystem Protection
Torizon OS uses OSTree for filesystem management, which mounts the rootfs as read-only to improve device security and reduce corruption probability (1). Additionally, when Secure Boot is enabled (which may be the case with your image), Torizon OS implements root filesystem protection using composefs technology integrated with OSTree (2).
Why Your Modifications Caused Boot Failure
When root filesystem protection is active, the system uses integrity verification mechanisms (2). The boot failure occurs because:
- Integrity Verification: The system verifies the integrity of filesystem components during boot using cryptographic hashes (2)
- Modified Files Break Verification: When you overwrote files directly, you changed their content, which breaks the integrity verification process
- Boot Process Halts: The kernel fails to boot because the filesystem integrity checks fail
Key Technical Details
The root filesystem protection in Torizon OS provides integrity and authenticity guarantees (2). When composefs is integrated with OSTree:
- The system maintains cryptographic hashes of files for verification
- Any unauthorized changes to the root filesystem are detected during boot
- The protection prevents persistent modifications that could compromise system security
Recommended Recovery and Future Approach
For Recovery:
- You’ll likely need to reflash the device with a clean Torizon OS image using Toradex Easy Installer
- The filesystem integrity has been compromised and cannot be easily repaired
For Future Modifications:
Instead of directly modifying the root filesystem, use the proper Torizon OS customization methods:
- Use TorizonCore Builder for OS-level customizations (1)
- Use Container-based Applications for application deployment (1)
- Use Device Tree Overlays for hardware configuration changes
- Use OSTree’s proper update mechanisms for system changes
Important Note About /etc Directory
If you need to modify configuration files, be aware that with root filesystem protection enabled, the /etc directory becomes volatile - changes made at runtime are lost on reboot (2). This is by design for security purposes.
The system provides mechanisms to make specific files persistent when needed, but this requires proper configuration during image building (2).
Conclusion
Your approach of remounting the root filesystem as read-write and directly modifying files bypassed the integrity protection mechanisms, causing the boot failure. This is actually the security system working as intended - preventing unauthorized filesystem modifications from persisting.
For future development, I recommend using the official Torizon OS customization tools and workflows rather than direct filesystem modifications.
Best regards,
Toradex AI Assistant.
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