Hardware Failure

Nokia 7705 SAR partial boot then reload loop: Diagnose & Fix

Q: Where can I find the Nokia official documentation?

https://documentation.nokia.com — 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	Nokia
Operating system	SR OS / SR Linux
Category	Hardware Failure
Skill level	Intermediate to advanced
DIY-able?	Yes with CLI access; some scenarios need Nokia Customer Care + RMA.

If you have ever stared at a Nokia 7705 SAR that just refused to come up, you know the muscle memory: serial console at 9600 8N1, wait for the BOF> (Boot Options File) line, hope it actually paints. On SR OS / SR Linux the first move is always `show version` and `show chassis environment`. if those return cleanly the box is alive enough to talk to you, which is the difference between a ten-minute fix and an RMA paperwork morning.

I keep a small notebook of Nokia part-numbers next to the rack because the LED legend differs between hardware generations. The SR OS / SR Linux platform tends to tell the truth in `show` output before the front-panel LED catches up, so trust the CLI first.

This guide assumes you have console access and an active Nokia Customer Care entitlement. If the device is out of warranty, skip straight to the recovery section, most of the steps still apply, you just lose the RMA option at the end.

What this guide covers

Diagnose and recover from partial boot then reload loop on a Nokia 7705 SAR.

Step-by-step

Capture the boot console output to a file: this is the single most useful diagnostic.
Verify image integrity (md5sum or vendor checksum).
If the image is corrupt, re-download from the vendor site and copy back.
If the boot output references a hardware error (memory test fail, FPGA fail), open an RMA.
Try booting an older known-good image stored on flash.

CLI / commands

# Verify hardware state
show version
show chassis
show chassis environment

# Collect for Nokia Customer Care
admin tech-support

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 SR OS / SR Linux version?

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

Should I open a Nokia Customer Care 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 Nokia official documentation?

https://documentation.nokia.com. 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 Nokia fix guides → /nokia/
All vendor guides → /vendors/

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

References

Nokia support portal: https://customer.nokia.com
Nokia knowledge base: https://documentation.nokia.com
Nokia security advisories: https://www.nokia.com/about-us/security/vulnerability-management/
Open a case: https://customer.nokia.com

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

What changed recently?

Fault diagnosis on a Nokia 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.

Safety + preconditions

Before any work on a Nokia 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.

Verification checklist

After applying the fix on your Nokia device, confirm:

The original symptom is no longer reproducible.
Related features (status LEDs, app sync, paired accessories) still work.
The device responds to a soft reboot without the fault returning.
Any error codes that were on display have cleared.
Documentation (your service log, the brand companion app) reflects the change.

When to call Nokia 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.