Cisco ip phone 7911 stuck in boot loop after factory reset

[eng.sultan.b]

Hi,

I faced an issue with one phone in remote site at my company, the phone is not showing the call history so I tried to do a factory reset to check.

After I did the factory reset (by pluging the network cable while pressing # then enter the sequence 123456789*0#) the phone stuck in boot loop. it restarting over and over. Then I did a hard reset (using this sequence 3491672850*#) but now the screen is off and the lights are flashing and won't stop.

Please need your advice

Phone Model: 7911

CUCM version: 8.6.2.20000-2

the phone in remote office.

Thanks in advance

[Manish Gogna]

Hi,

The only solution looks to be to try the factory reset again with the phone connected to a known working switch port. If it does not work after the factory or hard reset then it will require a replacment.

Manish

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[Konnekt1911]

Good day eng.sultan,

To make this short and sweet, the second sequence of numbers you typed in was to reset the Firmware on the phone back to default versus the first sequence which is more of a configured data/history Factory Default(not 100% correct but enough for this situation).  At any rate, when you input the Firmware Reset sequence, the phone is depleted of all Firmware files and then looks to load the Firmware it shipped from Cisco with.  As long as you have this Phone Software Load within your CME/CUCM Telephony System, eventually the phone will find it, load it, and ultimately come back to life.  Thanks!

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[eng.sultan.b]

Hi Konnekt1911, Thanks for your reply.

The phone is not working till now :(

I tried to change the port, do the reset again, and waited for one day but with no luck!

Is there anything else I can do?

[Konnekt1911]

eng,

If the lights still illuminate once the phone receives power, I think the phone is still OK.  What you will have to do is find out which version Firmware it is looking to default to.  This will take some trial and error but this is what needs to happen.  Download older firmware sets of file loads for that phone and take turns with each version until it comes back to life.  Hope this helps!

*By the way you don't have to do the reset sequence anymore or it restarts the process, just adjust load and connect  and let it do its thing.  You will know when its ready*

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[eng.sultan.b]

Thanks Manish for your reply, I tried this solution yesterday but no luck :(

[Gordon Ross]

Wireshark is your friend here. Note that after performing a hard reset, you won't get anything on the display until the upgrade has completed.

GTG

[eng.sultan.b]

Hi Gordon,

It's hard using wireshark in my case because the phone in another city.

Thanks for your reply :)

[Gordon Ross]

At this stage, a packet capture is your only remaining diagnostic tool. If you can't get a packet capture, then you're going to have to guess what might be wrong...

GTG

[eng.sultan.b]

You are right, I will try my best.

Thanks my friend.

[Mohammed al Baqari]

Hi,

1. Start with checking show cdp ne #port-number# details and see if the phone is getting correct DHCP IP or not.

2. From CUCM try to ping the IP of the phone to check reachability

3. Check CUCM traces to look the phone mac address. See if the phone is requesting TFTP.

4. Try to get port span on the switch from the phone to a working machine at remote site then run wireshark to capture traffic from/to phone and see what it is happening.