Hardware Failure

Nvidia (Mellanox) SN3420 stuck at boot loader prompt: Diagnose & Fix

Q: Where can I find the Nvidia (Mellanox) official documentation?

https://docs.nvidia.com/networking/ — search the product family + feature name.

By Sai Kiran Pandrala · reviewed by Sai Kiran Pandrala, Editor Last verified: 2026-05-30

⚡ At a glance

Vendor	Nvidia (Mellanox)
Operating system	Cumulus Linux / NVOS / SONiC
Category	Hardware Failure
Skill level	Intermediate to advanced
DIY-able?	Yes with CLI access; some scenarios need Nvidia Enterprise Support + RMA.

Hardware-class faults on Nvidia (Mellanox) kit fall into a tidy little matrix once you have seen a few. Cumulus Linux / NVOS / SONiC gives you the building blocks via `nv show system` and `nv show platform environment`; the rest is pattern matching. The SN3420 platform is one of the more common offenders only because the install base is large.

Do not skip the visible-and-audible inspection. Burnt-PCB smell and fan-tray rattle are diagnostic signals that no command will ever surface. I have caught more dying PSUs by ear than by `nv show platform environment`.

If the chassis is dark and the console is silent, jump straight to the PSU/cable substitution path before opening a Nvidia Enterprise Support ticket, it eliminates the most common cause in under five minutes.

What this guide covers

Diagnose and recover from stuck at boot loader prompt on a Nvidia (Mellanox) SN3420.

Step-by-step

At the boot loader prompt, list available images.
If an image exists, boot it manually.
If no image (deleted or corrupt), pull a fresh image over TFTP or USB.
Set the boot variable to the recovered image.
Reset and watch for a normal boot.

CLI / commands

# Verify hardware state
nv show system
nv show platform inventory
nv show platform environment

# Collect for Nvidia Enterprise Support
cl-support (Cumulus) / show techsupport (SONiC)

When to RMA

Repeated failure after re-seat and power-cycle
Visible burn, scorching, or physical damage
POST or memory diagnostic failure
Hardware crashinfo without a software workaround

Frequently asked questions

Will this work on my specific Cumulus Linux / NVOS / SONiC version?

The procedure reflects current Cumulus Linux / NVOS / SONiC behaviour. Older releases may need minor syntax adjustments: use the CLI help (? or tab-completion) to verify.

Should I open a Nvidia Enterprise Support case immediately?

Open one if you suspect hardware failure or the symptom persists after a maintenance-window reload. Make sure your support entitlement is active first.

Where can I find the Nvidia (Mellanox) official documentation?

https://docs.nvidia.com/networking/, search the product family + feature name.

Is this procedure safe in production?

Test in a lab or maintenance window first. Capture pre-change state so you can roll back.

All Nvidia (Mellanox) fix guides → /nvidia/
All vendor guides → /vendors/

Related guides worth a look while you sort this one out:

References

Nvidia (Mellanox) support portal: https://enterprise-support.nvidia.com/
Nvidia (Mellanox) knowledge base: https://docs.nvidia.com/networking/
Nvidia (Mellanox) security advisories: https://www.nvidia.com/en-us/security/
Open a case: https://enterprise-support.nvidia.com/s/createcase

Reference material, not professional advice. Validate against your specific Cumulus Linux / NVOS / SONiC version and test in a non-production environment before applying.

Common patterns we see

When this symptom shows up on a Nvidia device, three patterns repeat:

1. Recent firmware update changed behavior. the symptom started within a week of an OTA push. Rollback or wait for the hotfix. 2. Environmental trigger, temperature, humidity, line voltage, network changes. Look at what changed in the environment. 3. Cumulative wear: components like batteries, gaskets, fans degrade over time. Replace the consumable rather than chasing a software fix.

Knowing which pattern applies saves time on the wrong fix.

Safety + preconditions

Before any work on a Nvidia device:

Unplug from mains for any internal-access procedure.
Discharge stored energy (capacitors in PSUs, residual battery charge) per manufacturer guidance.
Use ESD-safe handling for boards and modules, no carpet, no wool sleeves.
Avoid moisture; never apply liquids near vents or connectors.
If you smell smoke, see scorch marks, or feel uneven heat, stop and escalate.

How to confirm it's actually fixed

On a Nvidia device, the test is rarely "reboot and see". Use this list:

Active reproduction: trigger the original failure path on purpose.
Indirect reproduction: do an activity that would expose the same subsystem.
Status indicator review: every LED / display / app status should be green.
24-hour soak: leave the device under normal load overnight; check the next morning.
Telemetry check: review the device or app's diagnostic log for new error entries.

When to call Nvidia support instead

Escalate if:

The same symptom returns within 24 hours of a clean fix.
You see physical damage (burn marks, swollen battery, cracked PCB).
The device is in warranty and a hardware replacement is the cheaper outcome.
Repair requires specialised tools you don't own (alignment jigs, calibration software).
Following the official path keeps the warranty intact, which matters more than the time spent.