Cisco 1720 flash filesystem erased

Posted on 2007-09-28
Medium Priority
Last Modified: 2010-04-21
Cisco 1720 flash has been erased and there is no filesystem (so I can't download a new image).  I only have ROMMON> and can't find any commands to create a new FLASH: filesystem.   What steps do I take at this point to get to the point where I can download an image using XMODEM or IP?
Question by:dvanaken
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LVL 11

Expert Comment

ID: 19980943
1720 is capable of downloading over TFTP
You don't need to format flash.

For TFTP download you will need to set some Variables
IP_ADDRESS= ip_address
IP_SUBNET_MASK= ip_address
TFTP_SERVER= ip_address
TFTP_FILE= filename


Assisted Solution

yasirirfan earned 600 total points
ID: 19981781
Since your router is in ROMON mode its better to use XMODEM command to upload a new IOS here are the steps to do this job,

From the ROMmon prompt, issue the xmodem command. However, before you issue the xmodem command, ensure that you have the new Cisco IOS software image on your PC.

In this example, all Flash memory is erased before downloading using the f option (only on the Cisco 1600 Series ). Perform a CRC-16 checksum using the c option and using a download speed of 115200 bps (only on the Cisco 1600 Series ) by specifying -s115200:

rommon 12 >xmodem -cfs115200 c1600-sy-mz.121-16.bin
Do not start the sending program yet...Note: If the console port is attached to a modem, both the console port and the modem must be operating at the same baud rate.

Use console speed 115200 bps for download [confirm]
File size Checksum File name
1957444 bytes (0x1dde44) 0xe345 c1600-y-mz.113-9.TErasing flash at 0x83f0000 no partition 2 on device: PCMCIA slot 1

Ready to receive file c1600-sy-mz.121-16.bin ...
Download will be performed at 115200.
make sure your terminal emulator is set to
this speed before sending file. Warning:  

All existing files in the partition displayed and files in any
other partitions on this device will be lost! Continue ? press 'y'
for yes, 'n' for no:yConfigure the terminal emulator program for a data rate of 115200 bps to match the xmodem speed specified above. This is done by closing the previous terminal session of 9600 bps and opening a new one at 115200 with 8-N-1. The trick here is that the Cisco 1603 only supports a maximum baud rate of 9600 bps. Therefore, when connecting at 115200 bps, you cannot see the router prompt. This is an important point to remember. Once connected to the router at 115200 bps, select Transfer and Send File from the HyperTerminal menu bar.


Specify the image file name and location and enter xmodem as the protocol.


Click on Send to start the transfer.


This message is received when the transfer is complete:

Download Complete!

Returning console speed to 9600

Please reset your terminal emulator to this speed...Per the message above, you need to exit your 115200 bps HyperTerminal session and restart a new one at 9600 bps. Once connected, the router's ROMmon prompt appears. Verify that the download was successful by issuing a dir flash:.

rommon 9 >dir flash:
File size Checksum File name
3686656 bytes (0x384100) 0x1a5e c1600-sy-mz.121-16.bin
Change the config register back to 0x2102 and reset or power cycle the router so that the new Cisco IOS software image gets loaded.

rommon 10 >confreg 0x2102

You must reset or power cycle for new config to take effect.

rommon 11 >reset
System Bootstrap, Version 12.0(19981130:173850) [rameshs-120t_lava 114],
DEVELOPMENT SOFTWARE Copyright (c) 1994-1998 by cisco Systems, Inc.
Simm with parity detected, ignoring onboard DRAM
C1600 platform with 16384 Kbytes of main memory
program load complete, entry point: 0x4020060, size: 0x15568c
%SYS-6-BOOT_MESSAGES: Messages above this line are from the boot loader.
program load complete, entry point: 0x2005000, size: 0x3840e0

Self decompressing the image : ########################################

Cisco Internetwork Operating System Software
IOS (tm) 1600 Software (C1600-SY-M), Version 12.1(16),
Copyright (c) 1986-2002 by cisco Systems, Inc.
Compiled Mon 08-Jul-02 17:09 by kellythw
Image text-base: 0x02005000, data-base: 0x0275BD48




LVL 11

Expert Comment

ID: 19981889
This sample is for 1600 routers with external flash card. XMODEM is much slower then TFTP. Over TFTP it takes just few seconds for actual download. It's really helpfull if after XMODEM download the image refuses to work...
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Author Comment

ID: 19982287
Thanks, guys.  I actually know how to download the image.  The problem is that the FILESYSTEM itself does not exist on the FLASH.  I erased it when I was trying to delete the existing flash image file.  Now I can't do DIR (device error), etc.  I can't find a command to create the filesystem (dir structure, etc).  For example, when I  XMODEM the image, I get an error that there is no filesystem - can't write the file.  I am home for the weekend, but I can post the exact error Monday.  Thanks --Dale
LVL 11

Expert Comment

ID: 19982338
Use tftpdnld  -r command from rommon, load and start image from TFTP, then erase flash one more time from IOS and then load new image using "copy tftp flash" command. If it's not working, there is a chance of having damaged flash chip. I had a situation when all the content of the flash on 1751 just disapeared and flash refused to write anything on it.

Author Comment

ID: 19982417
Hey tvman-

Thanks for the ideas - I didn't think of loading the image into RAM and running it.  However, you breezed by a few steps there,  Can you give me some more details?  I'm not a router newbie but Cisco CLI is fairly new to me.  Thanks -Dale
LVL 11

Accepted Solution

tvman_od earned 1400 total points
ID: 19982551
For rommon operations, please see the link posted above. It has detaile description and step-by-step instruction

When your router will give you initial prompt for initial config, follow basic management config branch. Or just interrupt it and configure it manually. You will need to configure ethernnet interface first

#conf t
(config)#interface fa0
(config)#ip address <LAN IP> <LAN mask>
(config)#no shu

! then erase flash just in case
#erase flash:
! then copy a copy from tftp
#copy tftp: flash:
[IP]<enter IP of tftp server>
[source-filename]<IOS image file>
[destination-filename]<Enter key, will use the same as source>

#wr mem

If you need TFTP server for Windows, you can use this one

Author Closing Comment

ID: 31407958
Sorry it took me a long time to get back to this.

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