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New Member

Downgrade CSS OS

We have loaded CSS release, but our 11503 pair rebooted after a week so we wanted to rollback to

I ran the upgrade script and loaded, but on reboot the old ver did not get written to the modules, als operational flash is still

Does anyone know how to force the downgrade to operational flash and the modules? Or does it not even matter? The CSS is running fine woth no boot errors. Here's the example;

css# sh ver

Version:               sg0820303 (

Flash (Locked):

Flash (Operational):

Type:                  PRIMARY

Licensed Cmd Set(s):   Standard Feature Set

                       Secure Management

css# sh chassis flash

Configuration for CSS11506-2AC K0:

Product Name:    CSS11506-2AC K0    SW Version:

Serial Number:   xxxxxxxx        Base Mac Address:  xxxxxxxx

Slot/SubSlot  Operational                       Locked

   1/1        *             

   2/1        *             

   4/1        *             

css# sh installed-software



css# sh boot

!************************ BOOT CONFIG ************************

  ip address x.x.x.x

  subnet mask

  gateway address x.x.x.x

  primary boot-file sg0820303

  primary boot-type boot-via-disk

Any help greatly appreciated.

New Member

Downgrade CSS OS

Hi Julian,

What you experienced is not normal, did the CSS generate a core dump? if you do show core, are you seeing a file there? if yes, I will recommend you to open a TAC case so we can analyze that.

Regarding your question:

css# sh ver

Version:               sg0820303 (

Flash (Locked):

Flash (Operational):

The really important one is the Version output, Flash Operation is an historical for track purposes, of the latest code, that the CSS has ever used, so every time that you upgrade the code to the latest brand new code, that value is going to be updated, but if you do a downgrade, that will not cause any difference, so you do not need to worry about it.