Avaya cu360 android recovery

[rtorrezcabre]

Avaya CU360 was updated to the latest version CU-360_V11_4_0_38, once the update was completed the device restarted and remained on the initial screen of the Avaya logo. The avaya cu360 fails to load the operating system. It started in Android recovery mode, to recover factory data which does not work. An attempt was made to load firmware through USB storage and there was a signature verification error. The display on the screen is:
Install /mnt/external_sd/update.zip …
Finding update package…
Opening update package..
Verifying update package…
retv1 = 0
Launching Vog.sh script…
exec_cmd execution: args[0]=vog.sh
exec_cmd executed with status WEXITSTATUS(status) = 11
E:/vog.sh executed with status 11
retv2 = 11
vog verification failed
Going on with usual recovery checks
E:footer is wrong
ate package verification took 9.7 s (result 1).
E:signature verification failed
E:Error: 21

Please any idea to recover my device. thank you so much

[avc863552095966]

I have CU360 Product#700513892, S/N:20YT16000441, can't upgrade to the latest version.

so how do we downgrade to the old version and do the same up to Version: 11.04.00.0038 V11_4_0_38