auth fail error while IP Phone 7941 firmware upgrade from 9.1 to 9.4

[rajeshcv49]

Hi all,

we have cucm 8.6 and ip phone 7941, 7942 and 796.

all phone was running firmware version sccp41.9-1-1sr1s, Recently i have upload sccp41.9-41s* to all node cucm node in cluster and started upgrade to phones, i am was able to upgraded to 7961 phone but when try to upgrade to 7941 phone, It showing error " auth fail" and booting with old firmware version. 

all phones in remote location, TFTP connectivity is fine.

really appreciate help. 

[Jonathan Schulenberg]

You’re sure the 7941 phones actually have 9.1(1) installed on them? That symptom strongly suggests they are running 8.5(1) or earlier.
https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cuipph/firmware/8_5_3/english/release/notes/7900_853.html#wp57602

[rajeshcv49]

Thanks for your response,

I am sure that, All 7941 and 7961 phones have 9.1 firmware version.

I am able to upgrade firmware version 9.1 to 9.4 for few 7961 phones, but few other same version phones i am not able to upgrade( Auth fail error).

[Jonathan Schulenberg]

The only other explanation would be an ITL chain of trust breakage. You can try manually deleting the ITL from one of the phones, allowing it to take a blind leap of faith and accept the current ITL from CUCM (assuming it's not corrupt). That would allow it to accept a new XML configuration file telling it to download newer firmware.
https://www.cisco.com/c/en/us/support/docs/voice-unified-communications/unified-communications-manager-callmanager/116232-technote-sbd-00.html