TELNET hangs after firmware update to 15.3.4.6 or 16.1.3.6

[Bobby_Johnson]

We have experienced some errors that are preventing us from a full firmware update to several devices. The primary error occurs when attempting to make a TELENT connection. We are able to enter username and password, but then the session immediately hangs:
no display, no cursor, no keyboard responses.

The error occurs on multiple platforms while migrating from various versions of firmware to either v15.3.4.6 or v16.1.3.6. Here are a sampling of some of the affected devices:

Equip Model Current F/W New F/W
x650-24x 12.3.3.6 15.3.4.6
x650-24x 12.3.4.12 15.3.4.6
x460-48t 15.7.1.4 16.1.3.6
x460-24x 12.5.4.5 16.1.3.6
x450-48t 12.5.4.5 15.3.4.6
x450-48t 12.0.3.16 15.3.4.6
x350-48t 12.0.3.16 15.3.4.6

We're not sure if there is a problem with the XOS, setting, etc. The TELNET session hang DOES NOT OCCUR on all devices. We have successfully updated approx 75 already, but had to stop the update process once this error was discovered.

We have approximately 80 more devices to update, to which afterwards, they’ll have the SSH xmod installed. We appreciate any help or input you can offer.

Thanks,

Bobby

[Tripathy__Priya]

I could see out of some sample list of affected devices, you are trying to upgrade from 12.3 to 15.3 release or so. Actually from these releases of 12.3 or below if any can not be directly upgraded to the next major release. Rather it requires intermediate steps for upgrade from 12.3.x to 15.x.

Please find below the article showing the exact steps of upgrading the same:

https://gtacknowledge.extremenetworks.com/articles/Q_A/Upgrade-from-12-X-to-15-X