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unbrick 7975 phone?

Unanswered Question
Mar 18th, 2010
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so i accidentaly "destroyed" a 7975 phone. accidentally in this case means that someone (not me) reloaded a catalyst while the phone got its firmware updated. things like that happen, obviously.

ever since, the phone is bricked. it just won't boot (not even the white splash screen with the java logo shows up). the phone, however, tries to download the firmware from the call manager tftp server. there are no tftp errors (on the call server, the 7975's display is black).


i googled up some instructions on how to do a factory reset (press and hold # and cycle power, when the top right LEDs start to blink press 1234567890*0#), to no avail. the screen stays black and the phone reboots from time to time (short white flicker), that's it.


any chance to unbrick the phone? i don't want to RMA it, this is a PITA and takes ages, at least over here.




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lightxx1980 Fri, 03/19/2010 - 08:05
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big thx to David Trad for helping me recover that phone. :)

lightxx1980 Thu, 03/25/2010 - 23:22
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i had fatfingered some of my TFTP loads. once they where right i just let the phone sit over the night, when i came back to the office it had automagically recovered. when its 'bricked' it seems the phone is in an endless "maintenance mode" loop trying to get a valid firmware from the TFTP server. interestingly enough, it will definitely take some time and lots of retries for the phone to end that loop and continue with normal operation.

William Paulsen Fri, 03/26/2010 - 05:34
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Thanks.  So it sounds like your phone had an IP even in the bricked state?  Was it a DHCP-allocated IP?  (ie, in the router's DHCP client table)  (I have several bricked SPA525 phone that don't even get as far as having an ip)

lightxx1980 Fri, 03/26/2010 - 05:44
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with 7975 phones, if something happens during the FW update cycle (as it was in my case), the backlight of the screen gets disabled and the phone itself is stuck forever trying to update the firmware.

so the answer is yes, the phone still leased an IP from the DHCP server, was reachable via ICMP and actively tried to update its corrupt firmware.

keep in mind though that 79xx series phones are Java based and have an entirely different architecture than 525Gs


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