3850 switch – IOS XE upgrade Detailed

By default, the switches are shipped in Install mode.

Bundle mode: Bundle mode is where we boot the switch/stack using the .bin file. This is the traditional method of booting the switch where the switch extracts the .bin file to the RAM of the switch and run from there.

Install Mode: Install mode is where we pre-extract the .bin file in the flash and boot the witch/stack using the packages.conf file created during the extraction.

Install mode is the recommended mode of running the switch. Not all features may be available in this Bundle mode

Upgrading a stand-alone switch:
For example: boot flash:cat3k_caa-universalk9.SSA.03.08.83.EMD.150-8.83.EMD.bin

Hence, the boot variable should not be pointing to the .bin file. If so, the switch will boot in Bundle mode. The boot variable should be pointing to the “packages.conf” file in order for the switch to boot in Install mode.

Before doing the upgrade, we need to check the mode in which the switch is currently booted in.
show version | begin Switch Port

Switch Ports Model SW Version SW Image Mode
—— —– —– ———- ———- —-
* 1 32 WS-C3850-24T 03.03.01SE cat3k_caa-universalk9 INSTALL •ß Install mode


Cisco 3850 covert from bundle to install mode:
Current mode: BUNDLE MODE

1. dir flash: – Current running IOS version should be visible.
2. Expand the file to the flash file system.
#software expand running to flash:
it take running .bin file and expand the content to the flash file system so we
can then convert from bundle to install mode.

3. Verify once expanded, All pkg file should be expanded including the very important packages.conf file.
#dir flash:

4. Change the boot variable to point to the packages.conf file.
#boot system switch all flash:packages.conf
This will cover single to multiple switches in a stack.

5. Verify the boot
#show boot
verify the boot variable and build

6. wr mem
7. reload
8. show version | begin Switch Port
9. clean the bin file
#software clean
#wr mem

Replace a Failed Cisco 3850 Switch in a Stack
1. Connect to the new switch
2. Verify the license level and IOS version.
a. In order to avoid the license mismatch.
#license right-to-use activate ipbase all acceptEULA
3. Restart

On your stack, you need to make sure the new switch come up with the same software version.
Master(global)# software auto-upgrade auto
So when we connect the new switch it will auto upgrade the same version as
the stack.

Connect the stacking cable and the power of the new switch.

Cisco Catalyst 3850 IOS Upgrade on All Stack Members – Version Mismatch

1. Connect the switches to the stack
2. Verify the license level
3. On master
#request platform software package install auto-upgrade
Auto upgrade has been initiated for the following incompatible switch
4. Reload the new member

Cisco 3850 IOS switch stack 3.x.x to 16.x.x upgrade install mode
1. We need to make sure the we do have space available on the flash:
#software clean
2. Copy the bin file active switch flash
3. Once the file is copied over we are going to regenerate rsa cryto key use for SSH and the 16.x.x release notes if your upgrading from 3.x.x to 16.x.x to generate a new crypto key.
#crypto key generate key 1024
4. Begin the software upgrade
#software install file flash:filename switch verbose new force

New – we need to create a new packages.conf to be used by the boot up process.
force – this will force actual process, 1 major code to another.. otherwise package compatibility will fail.


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