Written by Sam McGeown on 9/2/2015 · Read in about 3 min (428 words)
Published under Networking

<img class=“alignright wp-image-5603 size-medium” src=“/wp-content/uploads/2015/02/cisco_SG300-20_1-300x180.png” alt=“Cisco SG300-20” width=“300” height=“180” of upgrading my lab switch, which is the excellent Cisco SG300-20, I’ve not had a chance to update the firmware since it was released 6 months ago because of the downtime. For some reason I prefer configuring the SG300 from the command line - a hangover from my old networking days I suppose, but somehow it doesn’t feel right to me to use the GUI!

I found an article by Chris Wahl which ran through the steps required to do it via the GUI. If you’re only interested in doing the update, then I suggest following Chris’ article - otherwise follow me for some CLI goodness!

Download the latest firmware from Cisco (at present -


Note: You can’t go directly from version 1.1.2 to - you have to use as an intermediate update

You need a TFTP server set up - I like Open TFTP Server but there are plenty of other free ones around - just unzip the firmware package from Cisco and place the two files (.ros and .rfb) in the TFTP root. It’s worth noting that the rfb file is a boot image, and the ros file is the firmware image.

It’s a pretty good idea at this point to back up your switch configuration and current firmware/boot image. Also, your switch will reboot a couple of times during the process so make sure nothing important is happening on the network - I shut down my whole lab environment.

Open a PuTTY session to your SG300 and use the below command to update the boot image first:

copy tftp://<tftp server/path/to/bootimage.rfb boot


Use “sh ver” to check that the Boot version is now correct:


Note: You can’t go directly from version 1.1.2 to - you have to use as an intermediate update

Use “wr” to ensure you current running-config is saved to startup-config and then “reload” to reboot the switch.

Once the switch has rebooted, SSH back in and upload the firmware package:

copy tftp://<tftp server/path/to/firmware.ros image


Now the image has been copied to flash but is not yet active, use “sh bootv” to list the versions available:


Check which filename is the new version and “not active” and then use the following command to activate it next boot:

boot system image-2

Once again, “wr” and “reload”. When the switch comes back up you can check it’s using the new firmware:



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