Dear NVIDIA Teams,
We hope this message finds you well.
We are currently utilizing the UEFI A/B slot functionality on the Jetson Orin platform with the R36.5.0 release. In our deployment, we have enabled the A/B partition redundancy and failover mechanism. However, we have encountered a critical issue: during the RAMFS stage, the init process may fail to boot due to various kernel panics or filesystem mount errors. When such failures occur, the system becomes stuck at the boot phase, and because systemd fails to trigger the watchdog mechanism, the device is unable to automatically fall back to the recovery mode or switch to the alternate partition.
To address this, our hardware design includes a reserved MCU that is intended to control pins B61 and B62 on the Orin module. We have reviewed the UEFI source code provided in the R36.5.0 release and observed that the current boot slot selection logic appears to rely solely on software-controlled parameters, such as the bootchain= boot argument or UEFI variables like BootChainOsCurrent and BootChainFwCurrent.
We would like to request your guidance on the following:
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Whether it is feasible to implement hardware-based boot slot selection using pins B61 and B62 on the Orin module within the R36.5.0 UEFI environment.
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Specifically, we aim to replicate the behavior observed in the latest Jetson Thor codebase, where functions such as T234GetActiveBootChain() are used to retrieve the active boot partition information, and ValidateActiveBootChain() is employed to mark or validate the boot path.
We would greatly appreciate it if you could provide any technical insights, patch recommendations, or configuration guidelines that would enable this GPIO-based boot control mechanism in the current R36.5.0 release.
Please let us know if additional details from our side would be helpful. We look forward to your response.
Best regards,
Hi yuhaibao,
On Jetson Orin r36.5, boot-chain selection appears to be driven by BR-BCT/scratch-register flow before UEFI, so GPIO-based A/B selection is likely not a stock supported UEFI feature.
For supported behavior, please use the documented A/B management path (nvbootctrl / Capsule update) rather than GPIO override in UEFI.
Thank you for your reply.
According to the pin configuration in the Jetson 7.2 Thor hardware pinout scheme, it is possible to use G5 (GPIO56_BOOT_CHAIN_SEL), C4 (I2S2_CLK_BOOT_CHAIN_1), and C55 (GPIO39_BOOT_CHAIN_0) together to control the A/B rootfs partition selection for switching. However, when comparing this with the pin configuration designed for Jetson Orin, it seems that the Jetson Orin hardware design does not reserve support for controlling A/B partition switching via dedicated pins.
Currently, we have a requirement: we would like to reserve a hardware design capability that allows an external MCU to control Jetson Orin via pins, enabling functional safety-level diagnostics and switching of the rootfs A/B partition boot chain. Could you please provide some guidance or support on this?
Additionally, I have another hardware-related question.
if we adapt the JP 7.2 codebase for Jetson Orin, which Orin pins should be reserved in the hardware design for the MCU to control the BOOT_CHAIN_1 and BOOT_CHAIN_0 states, in order to implement a functional safety diagnostics and switching strategy?
Thanks for the clarification.
Thor has a dedicated MCU-driven boot-chain pin mechanism, but Jetson Orin does not expose this as a standard customer-facing hardware feature.
For Jetson Orin, we recommend using the standard A/B software/BCT framework for rootfs or boot-chain switching rather than applying the Thor / JP 7.2 pin scheme directly.
If an external MCU-controlled boot-chain mechanism is still required, it should be treated as a custom design topic and reviewed separately.
Thank you very much for taking the time to provide your support despite your busy schedule.
Regarding the detailed design requirements for implementing an MCU-controlled boot chain mechanism on the Jetson Orin platform, we have created a new forum thread for further discussion. Please feel free to move the conversation to that thread.
New Forum Post Link: MCU-Controlled Boot Chain & Functional Safety Strategy for Jetson Orin
We look forward to your continued guidance on this topic.
Best regards,