How to upload the IOS in rommon mode

By | February 17, 2020

We can upload the IOS in rommon mode using below methods

  1. DNLD Process
  2. X-Modem

DNLD process is used to upload the IOS when router is in rommon mode and we are unable to upload the IOS in normal way because router don’t have any IP address or any other configuration in this mode. so we can’t upload the IOS using normal process. in this case we can upload the IOS using DNLD process or through X-Modem. Below is the DNLS process and i will explain X-modem process in another post.

Just remember the one word that is TFTPDNLD , other command syntax will be show on console automatically  when you will enter the tftpdnld command. so no need to remember all the commands. Before follow the below process , your desktop / laptop should be connected with router using straight or cross cable as well as console cable. Also make sure that  you are having tftp server application on your laptop and IOS image and you have given the path of IOS in TFTP server. You should also check that TFTP server is taking the IP same as your desktop / laptop and This IP should also ping from router. 

Rommon> dir flash:









WARNING: All existing data in all partitions of flash will be lost!

Do you want to continue? y/n:{n}: y


Explaining of commands:

IP_ADDRESS – It will set a IP address to your router

SUBNET_MASK – It will set subnet mask to your router

DEFAULT_GATEWAY – It will set the default gateway to your router

TFTP_SERVER – It will be a IP of your desktop/laptop, on which you are running the tftp server application

TFTP_FILE – This command will tell your router that which IOS file need to be download from TFTP server

Set- This command is used to display the configuration. so you can make sure that configuration is correct or not.

TFTPDNLD – if you are running this command in the starting then it will show you all  the command syntax. so you can follow the syntax and configure accordingly and no need to remember the bunch of commands. if you are running this command in last , that means this command will start the downloading of IOS.

3 thoughts on “How to upload the IOS in rommon mode

  1. Sonia Sharma

    Nice explanation….. Could you please post the easy steps for high CPU utilization. I’ve tried to find it on Cisco site but unable to understand so i want some simple and easy steps. Thanks in advance…


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