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At CentricsIT, we are your IT experts. When any IT maintenance issue arises in your data center we are here to help. If there is an error code you can’t fix, let us assist you in our monthly FixIT column. This month, we’re focusing on how to upgrade Cisco 3850 IOS using TFTP and USB.

The procedure to upgrade Cisco 3850 IOS is very easy but it is a bit different than the usual software image of previous switches i.e 3750 etc.

The main difference is that the Cisco 3850 switch runs IOS-XE so you have to copy the .bin file to the flash on the switch, and then install the software on the switch.

  1. Download the required image from the Cisco website
  2. Begin the install
  3. Reboot the switch

Step 1 – Copy the New Image to the 3850

3850-SW1#copy tftp flash
Address or name of remote host []?
Source filename []? cat3k_caa-universalk9.SPA.03.03.01.SE.150-1.EZ1.bin
Destination filename [cat3k_caa-universalk9.SPA.03.03.01.SE.150-1.EZ1.bin]?
Accessing tftp://…
Loading cat3k_caa-universalk9.SPA.03.03.01.SE.150-1.EZ1.bin from (via Port-channel1): !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Once the file has been copied, verify the new IOS is present in flash

3850-SW1#dir flash:

Directory of flash:/

46472  -rwx     2097152  Sep 22 2013 10:23:20 +00:00  nvram_config
46468  -rwx     1689445  Aug 22 2013 20:48:35 +00:00  asic_dump_reg-1.csv
46467  -rwx     1689445  Aug 22 2013 21:17:05 +00:00  asic_dump_reg-0.csv
46469  -rwx         114  Sep 13 2013 06:08:19 +00:00  express_setup.debug
46466  -rw-   223737704  Feb 12 12:01:30 +00:00  cat3k_caa-universalk9.SPA.03.03.01.SE.150-1.EX3.bin
38721  drwx        4096  Sep 22 2013 10:14:12 +00:00  mnt
77443  -rwx        1224  Sep 22 2013 10:13:17 +00:00  packages.conf
46470  -rwx         736  Sep 20 2013 18:34:18 +00:00  vlan.dat
69699  -rwx    74369252  Sep 22 2013 10:13:12 +00:00  cat3k_caa-base.SPA.03.02.02.SE.pkg
69700  -rwx     5808828  Sep 22 2013 10:13:12 +00:00  cat3k_caa-drivers.SPA.03.02.02.SE.pkg
69701  -rwx    32488292  Sep 22 2013 10:13:12 +00:00  cat3k_caa-infra.SPA.03.02.02.SE.pkg
69702  -rwx    30403764  Sep 22 2013 10:13:12 +00:00  cat3k_caa-iosd-universalk9.SPA.150-1.EX2.pkg
69703  -rwx    16079584  Sep 22 2013 10:13:12 +00:00  cat3k_caa-platform.SPA.03.02.02.SE.pkg
69704  -rwx    64580300  Sep 22 2013 10:13:13 +00:00  cat3k_caa-wcm.SPA.

1621966848 bytes total (1123991552 bytes free)

Step 1a – Copy the Software to the 3850 Using USB

The image for the 3850 is very big (250Mb+), so copying via TFTP can take a while. A much better solution is to use a USB stick.

The process is very simple and much easier than using tftp. All you need is a USB stick that is recognized by the switch and a console connection.

To copy the software to upgrade Cisco 3850 IOS:

  1. Copy the image file into the root of drive and insert the USB drive into the USB slot on the front of the 3850.
  2. From the Command line verify that the switch can recognize the file system.
  3. dir usbflash0:
  4. This should list all the files on your USB
  5. You now need to copy the image from the USB to the Flash of the switch.

copy usbflash0:cat3k_caa-universalk9.SPA.03.03.01.SE.150-1.EX3.bin flash:

Now proceed to the software install in Step 2.

Step 2 – Start the Install to Upgrade Cisco 3850 IOS

3850-SW1#software install file flash:cat3k_caa-universalk9.SPA.03.03.01.SE.150-1.EX3.bin switch 1-2

Please note the switch 1-2 command at the end will install the image onto switch 1 and 2 in your stack, so if you are running a stack of 8 switches you need to enter switch 1-8

This step will unpack the .bin file and install the software, after the software has installed you will be prompted to reboot, the switch will reload, and you can then verify you are running the new IOS

3850-SW1#sh ver | i INSTALL
*    1 32    WS-C3850-24T       03.03.01SE        cat3k_caa-universalk9 INSTALL
2 32    WS-C3850-24T       03.03.01SE        cat3k_caa-universalk9 INSTALL

If you have any further questions about how to upgrade Cisco 3850 IOS or other Cisco equipment, contact our dedicated IT support staff by calling us toll free at 1 (877) 531-7466. CentricsIT offers data center services including data center hardware maintenance and support, and we can help you get the most out of your data center, regardless of its size.

Want more out of your Cisco hardware? Contact a Support Specialist at CentricsIT to employ a more proactive approach to your IT lifecycle management.