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Can Router Boot without Flash

Ahmed Chowdhury


      i have a 2801 router and its flash is damaged. so i cant use the router bcoz it cant boot up. is there any way that for the time being the router will boot up from the ios file stored in tftp server rather than flash. there will be no system board flash. pls help me out. thanks in advancee...

11 Replies 11

Reza Sharifi
Hall of Fame Master Hall of Fame Master
Hall of Fame Master

Hi Ahmed,

You can use this command to boot your router from the TFTP server

Make sure you have the image in your TFTP server.

boot system tftp



Thank u reza. one more question is that if i want to do this configure on rommon mode is this possible. or how can i config my router in rommon mode to load the ios from tftp server. thanks in advancee

Hi Ahmed,

You can use "tftpdnld" command/procedure to boot the router from rommon mode. Please see the link below on the process.

HTH, Please rate if it does.


-amit singh

thank u amit but the doc u provided is for if my flash is corrupted then next time when the router boots up in rommon then i will be a able to download the ios from tftp to my flash. but my dear my question is that i have no that case the router have to load the ios only from tftp server. is there any way to complete this task in rommon mode.

Hi Ahmed,

Try following the follwoing procedure in order to get an image on router from tftp server while the router is in rommon mode.

We will use the tftpdnld command, you have to use tftpdnld -r, but you have to set some
variables first.  The variables that you must specify include the following:
* IP_ADDRESS-IP address for the 2851 gateway.
* IP_SUBNET_MASK-Subnet mask for the 2851 gateway.
* DEFAULT_GATEWAY-Default gateway for the 2851.
* TFTP_SERVER-IP address of the server from which you want to download
the image file.
* TFTP_FILE-Name of the file that you want to download.

     rommon 16 > IP_ADDRESS=
     rommon 17 > IP_SUBNET_MASK=
     rommon 18 > DEFAULT_GATEWAY=
     rommon 19 > TFTP_SERVER=
     rommon 20 > TFTP_FILE=c2800nm-ipbase-mz.123-14.T7.bin
     rommon 21 > tftpdnld -r


Invoke this command for disaster recovery only.
WARNING: all existing data in all partitions on flash will be lost!
Do you wish to continue? y/n: [n]:
Enter y to begin downloading the Cisco IOS software image. When the
process is complete,
the ROM monitor mode prompt appears on your screen.  Then you can type
reset to boot with
the image, don't turn off the router.


but my dear my question is that i have no flash

The question what I'd like to ask is why can't you get a CF?

Hi ,

Yeah i agree ,my order to complete teh above procedure also we would need the flash on the router.



Leo Laohoo
VIP Community Legend VIP Community Legend
VIP Community Legend

Hi Swati,

This won't work.  It won't work because the router does not have a working CF.

The "-r" switch at the end of the command loads the ios directly into ram without touching flash.  I have booted this way without any cf or usb flash installed on a 2801.



Just checking


Were you successful in booting from tftp without the flash memory, using the switch?

Joseph W. Doherty
Hall of Fame Master Hall of Fame Master
Hall of Fame Master
I recall, on 2811s, the later bootstrap versions also supported IOS booting from USB (limited to what USB would work, beyond Cisco's). Don't recall if same available on 2801 (or if they even have a USB slot).
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