Skip to content

Documentation: Adding custom persistent partition that survives A/B updates #2335

Description

@ahmed-chrif

Documentation: Custom persistent partition for A/B update state storage

Summary

Successfully implemented a custom persistent partition (permanent_user_storage)
that survives A/B rootfs updates on Jetson Orin Nano. This addresses a gap
identified in #2282 where developers need persistent storage for SWUpdate
Suricatta/hawkBit state and other use cases requiring data persistence across
slot switches.

Context

Users need persistent storage that survives A/B updates for:

Environment

  • Hardware: NVIDIA Jetson Orin Nano
  • meta-tegra branch: 36.5.x (Scarthgap)
  • Yocto release: Scarthgap

Problem

The default NVIDIA partition layout on Orin has no dedicated persistent
data partition that survives A/B updates. The cboot bootloader environment
doesn't support T234 (Orin) for storing state, and U-Boot isn't available
on this platform.

Working Solution

Added custom partition using full flash layout XML override:

# tegra-storage-layout_%.bbappend
FILESEXTRAPATHS:prepend := "${THISDIR}/files:"
SRC_URI += "file://flash_l4t_t234_nvme_rootfs_ab.xml"

PARTITION_FILE_EXTERNAL := "${TOPDIR}/../meta-<your-layer>/recipes-bsp/tegra-binaries/files/flash_l4t_t234_nvme_rootfs_ab.xml"

Custom partition inserted before APP and APP_b. First-boot systemd service
formats as ext4 and mounts at /mnt/persistent.

Key Technical

tegra-binaries disables standard fetch/unpack; immediate expansion (:=)
is required for PARTITION_FILE_EXTERNAL
Partition appears as /dev/nvme0n1pXX (device node path)
Label symlink not automatically created, use direct path for mounts

Proposed Documentation

I can contribute documentation covering:

  • Why persistent storage is needed (including use cases like #2282)
    
  • Full custom XML approach with PARTITION_FILE_EXTERNAL
    
  • Required bbappend configuration
    
  • First-boot formatting and mounting with systemd
    
  • Path resolution pitfalls and binary recipe quirks
    

Related

#2282 - Request for Suricatta/hawkBit persistent state storage

Would this documentation be useful to merge? Happy to submit a PR.

Activity

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Type

    No type

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions