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Leo Laohoo
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Cisco 3850:  IOS-XE/Firmware Upgrade

(Install Mode)



  • This procedure is aimed at Cisco 3850 switch ONLY.
  • IOS-XE Bundle Mode is not covered. 
  • 9300, 9500 (vanilla & high-performance), ISR 1k, ISR 4k and ASR is not covered. 
  • Router(s) & switch(es) running “classic” IOS is not covered.


A Word from our Sponsors:

There is a very fine line between writing something short-and-sweet and writing something comprehensive while losing the target “market” in the process.  I have done all I can to make this document as “digestible” as possible without losing much of the important content but still maintaining some forward momentum. 



Switch and/or router firmware had (past tense) a simple procedure, however, for IOS-XE each platform has different commands, process & procedures, and “gotchas”.  Because of this, I have broken up the process into different sections:  9300, 9500 & routers.


Section 1:  General Procedure

Section 2:  Install SMU

Section 3:  GOTCHA

Section 4:  Emergency-Install


Section 1:  General Procedure

  1. Read the Release Notes very carefully.
  2. IOS-XE firmware and SMU files have a filename extension of “bin”. 
  3. Clean the flash:  install remove inactive

NOTE:  Switch/stack on IOS-XE version 3.X.X, uses a different command:

software clean force

  1. Copy the file into the switch/stack.
  2. Make sure the boot-variable string is pointing to “packages.conf” file. 


  1. Initiate Install Mode (Non-Disruptive/Do NOT Reboot 

request platform software package install switch all file flash:filename.bin on-reboot new auto-copy verbose


NOTE:  If upgrading from 3.X.X, the command is different: 

software install file flash: filename.bin new force verb on-reboot



  • If the file extraction is successful (or not), the last two lines will display the result. 
  • Go to the GOTCHA section if the following (image below) appears:


  1. Inspect the contents “packages.conf” file.  Is this the intended version or not?  If NO, go to the GOTCHA section.  Command:  more flash:packages.conf | begin for NOVA



  • If the switches are in a stack, inspect the “packages.conf” of each switch stack member.

more flash-1:packages.conf | begin for NOVA

more flash-2:packages.conf | begin for NOVA

more flash-3:packages.conf | begin for NOVA


more flash-8:packages.conf | begin for NOVA

  • If the switch is standalone, the command is: 

more flash:packages.conf | begin for NOVA

  1. REBOOT the switch/stack.
  2. [RECOMMENDED][OPTIONAL] Clean the flash:  install remove inactive
  3. DONE.


Section 2:  Install SMU

Software Maintenance Update (aka “patch”)


  • Only routers and switches running IOS-XE support SMU. 
  • Router(s) & switch(es) running “classic” IOS do not support SMU.
  • IMPORTANT:  Always treat SMU update as disruptive (reboots the switch/stack). 
  • IMPORTANT:  SMU file is platform-specific.
  • IMPORTANT:  SMU file is version-specific. 


Image (above):  Sample SMU filename


Image (above):  Attempting to install an SMU meant for a different version.



  1. Read the Release Notes very carefully.
  2. SMU firmware have a filename extension of “bin”. 
  3. Copy the SMU file into the switch. 
  4. Install the SMU: 

install add file flash:SMU_filename.bin activate commit


WARNING:  Immediately after entering “y” may/will cause the router &/or switch to reboot.


  1. Verify the SMU has been successfully installed.
  • Fast Method:  sh version | begin Active SMU


  • Slow Method:  sh install summary9.png
  1. DONE.

Section 3:  GOTCHA

  1. If the message (image below) appears at the end of the package extraction process THIS IS NOT A FALSE POSITIVE. 


  1. Check the contents of the flash/bootflash and compare the date stamp of the extracted packages against the date stamp of the “packages.conf” file (see image below). 


  1. Look in the flash/bootflash directory for two (2) files with an extension of “conf”.  (Image below)


  1. First, rename “packages.conf” to, say, “packages.conf.bak”.
  2. Next, rename the firmware.conf to “packages.conf” (see below).


  1. Check the contents of the new “packages.conf” file.  Is this the target version?   


  1. Inspect the contents of each “packages.conf” file of every member of the stack. 
  2. Make sure the boot-variable string is pointing to the “packages.conf” file.
  3. DONE. 

Section 4:  Emergency-Install

WARNING:  Emergency-Install command will erase the flash/bootflash of the appliance

(Make sure the config is stored somewhere else.)

  1. Emergency-Install is to be used when the switch boots into ROMMON. 
  2. The “emergency-install” command can only be used in ROMMON. 
  3. Emergency-Install process can only be effectively achieved by using a USB thumb drive.


Image above shows failed “emergency-install” because the firmware is in the flash. 


WARNING Emergency-Install command will erase the flash/bootflash of the appliance.  

  1. Command:  emergency-install usbflash0:filename.bin
  2. DONE.

Great, Thanks for sharing.


Hi Leo,

What SSH client are you using?



Leo Laohoo
Hall of Fame
Hall of Fame


thanks a lot for detailed explanation



i have just upgraded 3850 Core switche stack, and wanted to report a remark, during upgrade process,

Instead of using the command:

*boot system switch all flash:cat3k_caa-universalk9.16.12.05b.SPA.bin

It is better to use the following commands, specifying the switch ID.

*(config)#boot system switch 1 flash:cat3k_caa-universalk9.16.12.05b.SPA.bin

*(config)#boot system switch 2 flash:cat3k_caa-universalk9.16.12.05b.SPA.bin

Because the first command strangely places the firmware in second boot !!! So it does not take the new version on the next reboot.






Leo Laohoo
Hall of Fame
Hall of Fame


1.  Why would I want to specify what each member of the switch what to boot when I can perform a single command from the switch master? 

2.  The command you mentioned is for Bundle Mode.  This entire process talks about Install Mode.  


@Leo Laohoo 

yes, what i report concern Bundle Mode. i just wanted to share this with users could have the same issue.



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