Dear Nvidia team,
We have a technical question regarding the specific conditions that trigger a fallback in the A/B switch mechanism.
As we understand, during OTA updates, NVIDIA supports A/B partitions to ensure that if a failure occurs, the system can revert to the previous working slot. However, the exact conditions that cause the system to trigger this fallback are not clearly documented.
We are also confused with A/B switch about firmware and A/B switch about rootfs.
We would greatly appreciate any clarification, documentation, or guidance you could provide on this topic. Your support will be very helpful to us.
Thank you in advance!
Best regards,
Hi yanlin.li,
What’s your Jetpack version in use?
There are 2 kinds of redundant A/B system on Jetson Orin NX, one is Bootchain A/B which includes MB1/MB2/bpmp/bootloader..etc(flash_t234_qspi.xml) inside the QSPI and another is Rootfs A/B which includes kernel/rootfs/DTB..etc (flash_l4t_t234_nvme_rootfs_ab.xml) in external storage.
Bootchain A/B is enabled by default, and you can refer to Update and Redundancy for details.
Rootfs A/B is optional and you can enable it through adding ROOTFS_AB=1 in flash command, and you can refer to Root File System Redundancy for details.
Please also refer to the following threads for A/B redundancy use cases.
Query: Question about A and B partitions - #3 by KevinFFF
Logic: Reset Timing of Boot Retry Count - #7 by KevinFFF
Verification: Rootfs A/B redundancy fail-over mechanism in Jetpack5.1
What’s your Jetpack version in use?
We are using Jetpack 36.1
We have a specific problem with the slot switching. The board is flashed with ROOTFS_AB=1 and we boot into slot A . Then we switch to slot B using command nvbootctrl set-active-boot-slot 1 && reboot . That works and it reboots into slot B. Then we are trying to switch to slot A nvbootctrl set-active-boot-slot 0 && reboot . But the board still boots into slot B. How to make it switch back to slot A ?
Hi @aleksei.fedotov,
Are you working with @yanlin.li ?
There might be something wrong and it tried to boot from slot A failed so that it still boots from slot B.
Please share the full serial console log at this moment.
Hi @KevinFFF ,
Thank you very much for your help. Yes, @aleksei.fedotov and I are in the same team, and Aleksei is working on the A/B switch.
Best regards,
Yanlin
Okay, please share the full serial console log when it fails to switch back to Slot A.