A/B dual boot redundancy on L4T 35.1.0


I recently updated from L4T 32.6.1 to 35.1.0. I use the Jetsone Xavier NX devkit with eMMC and had set up unified bootloader/rootfs A/B slots redundancy with the 32.6.1 release of L4T. This basically meant using the following elements:

  • flash_l4t_t194_spi_emmc_p3668_rootfs_ab.xml
  • smd_info.rootfs_AB.cfg and nv_smd_generator
  • nv_update_engine and nvbootctrl

With the latest release, I could partition my eMMC correctly using the newer .xml. However, the nv_smd_generator is no longer available, and other tools report an error:

root@myboard:~# /usr/sbin/nv_update_engine -v
Nvidia A/B-Redundancy Update tool Version 2.0
verifying update
Verify bootloader update begins.
Warning: not support yet!
SM: S21
Checking whether Slot-A/B Redundancy and autosync are enabled.
Warning: not support yet!
Warning: not support yet!
Error: Verify bootloader update failed!
Verify rootfs update begins.
RootFS A/B is not enabled, verification finishes.
root@myboard:~# nv_update_engine -e
Nvidia A/B-Redundancy Update tool Version 2.0
enabling A/B redundancy
Segmentation fault
root@COM21000000:~# nvbootctrl is-autosync-enabled
Warning: not support yet!
Error querying the status of autosync: Operation not supported
root@myboard:~# nvbootctrl verify             
Info: variable BootChainFwStatus is not found.
root@myboard:~# nvbootctrl toggle-autosync
Warning: not support yet!
root@myboard:~# nvbootctrl dump-slots-info
Current bootloader slot: A
Active bootloader slot: A
num_slots: 2
slot: 0,             status: normal
slot: 1,             status: normal

The documentation regarding how to set up slots redundancy seems to have been updated and indeed shows support for some features is not yet available. However it does state that slots redundancy should work and be enabled by default despite the limited tools. Yet, I can’t use nvbootctrl to boot on the second (B) slot with the following command:

nvbootctrl set-active-boot-slot 2

My queries are the following:

  1. How can I make slots redundancy work on my hardware and current L4T version?
  2. Is there planned support for the missing features of the tools I mentioned?

Thank you kindly for your assistance,

hello enguerrand.de-ribaucourt,

there’re slot-0 and slot-1, you should toggle to second (B) slot with… $ nvbootctrl set-active-boot-slot 1.

r35.1 has default behavior, rootfs slot is tied together with bootloader slot.
and… in the next release (i.e. l4t-r35.2), rootfs slot is always tied together with bootloader slot.

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