Loading IOS on a WS-C3850 Switch

• Connect to the serial console
• Connect the Mgmt interface to your network
• Configure the Mgmt network interface (that's GigabitEthernet 0/0)
• Test connectivity:
  • ping vrf Mgmt-intf 192.168.1.11 or
  • ping vrf Mgmt-vrf 192.168.1.11
• Set Mgmt interface as interface to use for TFTP transfer:
  • conf t
  • ip tftp source-interface gigabitEthernet 0/0
  • exit
• Copy the .bin file to flash: via TFTP
  • copy tftp: flash:
• Install the .bin file using this command:
  • software install file flash:cat3k_caa-universalk9.SPA.03.07.01.E.152-3.E1.bin
  • Answer yes when asked if you want to relaod the switch
  • Answer no when asked if you want to save the configuration
• If you have a stack of 3850 switches, this only needs to be done on one stack member. The software will be upgraded on all stack members.

If downgrading from a newer IOS version, you may have to follow these instructions: https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/16-3/release_notes/ol-16-3-3850.html#34555 In a nutshell:

• Configure network connectivity as above
• Clean old packages: request platform software package clean switch all file flash: (confirm with "y")
• Copy new bin file from tftp server to flash
• Install (downgrade to) new bin file: request platform software package install switch all file flash:whatever-filename.bin new auto-copy