Upgrade Cisco Router IOS via TFTP Server

Upgrading IOS in routers is quite easy. For this, we need to install TFTP server. There are many free TFTP servers available on the internet and you can download one from http://tftpd32.jounin.net/   Before doing the upgrade, make sure that you either have backed up your IOS image or you have a newer one.

  • Okay, now first things first. Disable other networks and set up a static IP address on your computer on which TFTP server is installed. I am giving my computer a static IP address of 192.168.1.1 with subnet mask 255.255.255.0
  • Open your TFTP server, browse it to the folder where your IOS image is kept.

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  • Now, open your hyper terminal. Before upgrading the IOS, make sure that you have deleted the older one by typing the command:
    Router# delete flash:

delete-flash

It will then ask you for the file name, type  correctly the name of your file. You can look for the file name with command “show version”.

  • Now type in the following commands in rommon mode: (make sure you connected a cable to your g0/0 port of your router.)
IP_ADDRESS=192.168.1.2

IP_SUBNET_MASK=255.255.255.0

DEFAULT_GATEWAY=192.168.1.1

TFTP_SERVER=192.168.1.1

TFTP_FILE=c1841-ipbase-mz.124-3i.bin

Tftpdnld

Type ‘yes’ when it asks if you want to continue and then type reset to restart.

So  you just upgraded your IOS. Enjoy!

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Recovery of Corrupt or absent IOS on cisco switch

First, enter rommon mode by unplugging and plugging the power cable back and press the mode button for few seconds. Also, keep in mind to set the BUAD rate as high as possible to speed up the downloading process.

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Once you are in rommon mode, type the following commands,

Switch: flash_init

Switch: reset

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In enable mode, type command to delete old or corrupt flash (this command is going to take a few moments).

Switch# erase flash:

Switch# reload

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You can verify it with  # dir flash:

After you finish booting, you will enter rommon mode as there is no ios. Type,

switch: copy xmodem: flash:c2960-lanbase-mz.122-35.SE5.bin

go to Transfer Tab “Send File…” browse the file on desktop and the protocol is “Xmodem”

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This is going to take while. Once you finish this, type:

unset BAUD

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Establish a new connection with default setting and reset to restart the switch or simply type switch: boot to load ios. With this, we are done and you can use your switch. 🙂