Arista 7800R3 won't boot at all: Diagnose & Fix

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

What this guide covers

Diagnose and recover from won't boot at all on a Arista 7800R3.

Full fix path

1. Confirm power: PSU LED is green? Cable seated? Wall outlet live?
2. Try a known-good power cable + outlet.
3. If the device has multiple PSUs, try with only one PSU at a time.
4. Connect the console cable and watch for ANY output during power-on.
5. If completely dark (no LEDs, no console), suspect the PSU or motherboard.
6. Confirm warranty status, open a Arista TAC case, prepare for an RMA.

CLI / commands

# Verify hardware state
show version
show inventory
show environment all

# Collect for Arista TAC
show tech-support | redirect file:show-tech.log

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 Arista EOS version?

The procedure reflects current Arista EOS behaviour. Older releases may need minor syntax adjustments: use the CLI help (? or tab-completion) to verify.

Should I open a Arista TAC 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 Arista official documentation?

https://www.arista.com/en/support/toi, 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.

Related guides

• All Arista fix guides → /arista/
• All vendor guides → /vendors/

References

• Arista support portal: https://www.arista.com/en/support
• Arista knowledge base: https://www.arista.com/en/support/toi
• Arista security advisories: https://www.arista.com/en/support/advisories-notices
• Open a case: https://www.arista.com/en/support/customer-support

Reference material, not professional advice. Validate against your specific Arista EOS version and test in a non-production environment before applying.

What changed recently?

Fault diagnosis on a Arista device goes faster when you map the symptom to a recent change:

• Did firmware update in the last 7 days?
• Did the network (router, ISP, VPN) change?
• Was the device moved physically?
• Did paired devices (phone, hub, app) update?
• Were any accessories swapped in or out?

The answer narrows the root cause to a manageable subset.

Quick triage

A few things to confirm so the Arista device fix goes cleanly:

• Latest firmware downloaded if you're going to update.
• Warranty + support contract status checked. opening sealed parts may void it.
• Backup of current configuration (where applicable) taken.
• Spare parts on hand if you anticipate replacement.
• Adequate workspace, lighting, and time, rushing causes regressions.

Confirm it stuck

On a Arista 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.

Escalation guide

For a Arista device, the right escalation depends on impact:

• Cosmetic / minor: log a ticket via the Arista app or web portal. Response 1-3 business days.
• Mid-impact: phone support. Have your serial number ready.
• Critical (production down, safety issue): in-person dealer / TAC visit. Bring proof of purchase.
• Out of warranty: third-party repair shop with manufacturer-certified technicians.

More frequently asked questions

Does this affect other devices on my network?

Generally no. The procedure is local to this device. Network-side changes (firmware updates that affect TLS, SMB, or routing) are flagged explicitly in the steps.

What if the fix returns after a reboot?

Persistent fault returns mean either: a hardware fault (escalate), a configuration that's being overwritten by a sync source (check cloud profiles), or a regression in a recent firmware update (rollback).

Can I roll this back if something breaks?

Yes for software-level changes (firmware rollback, config rollback). Hardware changes are usually one-way. Always back up settings before starting.

Are there safer alternatives for non-technical users?

Yes: the manufacturer's self-service troubleshooter (HP Smart, LG ThinQ, Samsung Members, similar) usually walks through the same steps in a guided UI. Use that first if you're not comfortable with menu paths.

Why is this happening on a brand-new unit?

Out-of-box defects do occur. If you've owned the device under 30 days and the symptom persists after a factory reset, escalate to the seller for replacement under DOA terms before opening a manufacturer support case.

Field notes from real incidents on Arista

When I work on Arista 7800R3 won't boot at all: Diagnose & Fix the rhythm I lean on is the one I have built over years of these tickets, not a stack of generic advice. EOS-API (eAPI) over HTTPS is the cleanest way to script Arista at scale; do not wrap CLI screen-scraping when eAPI returns JSON. CloudVision Portal alerts are noisy unless you tune them; I disable the defaults and re-enable the ones that map to actual production events.

Show tech-support detail is the artifact Arista TAC expects on call one; bundle it with the agent logs before you open the ticket. Arista EOS lets you reload a module without reloading the chassis on most platforms, I use that capability more than people realise.

Tools I actually reach for

For Arista 7800R3 won't boot at all: Diagnose & Fix on Arista the cheapest signal I can land usually comes from a known order of operations, not a kitchen-sink approach. I start with show running-config | include <feature> because it is the lowest-friction way to confirm the failure is real and reproducible. If that returns ambiguous data, I escalate to show interfaces counters errors, traceroute vrf <vrf> <target>, show tech-support (capture for TAC), and finally to packet capture on the ingress interface (TAC will ask for it) only when the cheaper tools cannot reach the layer the failure lives in. That ordering matches the failure surfaces I have actually seen on Arista units over the last few years, not an abstract taxonomy. The cheap signals gate the expensive ones so the investigation does not balloon into a multi-hour exercise.

Verification I run before I close the ticket

Before I mark Arista 7800R3 won't boot at all: Diagnose & Fix resolved on a Arista unit, the verification loop below is what I actually run. Each step proves a different layer is green, and the order matters - the cheap checks gate the more expensive ones so I never burn an hour on a deep test that a shallow one would have failed in seconds.

show ip route <prefix>  # confirm best path post-change

If that one comes back clean, move to the next check. If it does not, stop and dig in there before layering more verification on top of a red signal.

show spanning-tree summary  # confirm topology stability

If that one comes back clean, move to the next check. If it does not, stop and dig in there before layering more verification on top of a red signal.

show bgp summary  # confirm session state after route changes

If that one comes back clean, move to the next check. If it does not, stop and dig in there before layering more verification on top of a red signal.

show logging | include %LINK|%LINEPROTO|%BGP|%OSPF

Only when every line above runs clean do I close the ticket and update the runbook with the timestamps. A green verification that nobody can reproduce is not a fix, it is luck waiting to regress.

Where I check first when the docs disagree

When two sources contradict each other on a Arista detail, the disambiguation order I lean on is stable across products and across years. eos.arista.com for the official software documentation is where I start for the ground-truth view. arista.com/en/support/product-documentation for EOS command references is where I start for the ground-truth view. Arista TAC knowledge base is where I start for the ground-truth view. Random blog posts and reseller wikis are signal, not ground truth, and I treat them as such until the references above either confirm or contradict the claim. The cost of trusting an unauthoritative source on Arista 7800R3 won't boot at all: Diagnose & Fix is rarely worth the time it saved.

Pitfalls I have walked into on this exact path

The shortcuts that look smart on Arista 7800R3 won't boot at all: Diagnose & Fix have a habit of biting back. The pitfalls below are the ones I have personally walked into on a Arista unit, not things I read about. CloudVision Portal alerts are noisy unless you tune them; I disable the defaults and re-enable the ones that map to actual production events. Arista EOS lets you reload a module without reloading the chassis on most platforms. I use that capability more than people realise. Show tech-support detail is the artifact Arista TAC expects on call one; bundle it with the agent logs before you open the ticket. When in doubt I revert to the slower path that the manual prescribes - the time I save by skipping it is always smaller than the time I spend cleaning up afterwards.

What I tell the next on-call

When I hand Arista 7800R3 won't boot at all: Diagnose & Fix off to the next person on rotation, the three lines I leave in the runbook are these. First, the symptom signature on Arista - not a paraphrase, the exact string that surfaces in logs or on the screen. Second, the diagnostic that gave the highest signal in the least time. Third, the exact verification command whose green output justified closing the ticket. That trio is what turns a one-off fix into a runbook entry the next engineer can use without paging me at three in the morning.

I also add a one-line note on the cost of getting this wrong. For Arista 7800R3 won't boot at all: Diagnose & Fix on a Arista unit, the cost is rarely the replacement part or the patch itself. It is the downtime, the second site visit, and the trust deficit you spend with whoever owns the asset when the fix does not hold. That framing keeps the next on-call from choosing the cheap-looking shortcut that ends up costing the most in elapsed hours and goodwill.

Related fixes

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

• Arista 7010T won't boot at all: Diagnose & Fix
• Arista 7050X3 won't boot at all: Diagnose & Fix
• Arista 7060X4 won't boot at all: Diagnose & Fix
• Arista 7060X5 won't boot at all: Diagnose & Fix
• Arista 7060X6 won't boot at all: Diagnose & Fix
• Arista 7280R won't boot at all: Diagnose & Fix