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3845 software upgrade


due to a bug on 12.3.(14)T2 we are instructed to upgrade to 12.3.(14)T5 for the 3845 router. This software includes snasw and we want this in order to guide the x.25 calls (qllc) over the Enterprise Extender connection to the Mainframe.

The problem is that the flash is 64MB and the already existing image is 34MB. The new image is also 34MB. So even if I delete all other files from flash, there is not enough space for having both images there.

Which is your suggestion?

If I delete the old image to free space, what are the consequences?

Regards, Apostolos.


Re: 3845 software upgrade


The best approach is to backup ur current ios and start proceeding with the update.

Since the IOS file size is more than 16MB i think u need to use FTP services instead of TFTP to upload the new code.

Use the most recommended ftp server s/w such as 3Com or other freewares.

Once you are thru with backuping ur current ios u can start proceeding in erasing the code in the flash and start uploading the new code onto the flash.

if possible i would suggest to connect both the FTP server and the router back to back using cross cable.

if its not possible then would suggest to take care of the dependencies like switch in which both the router and the FTP server is getting connected..


New Member

Re: 3845 software upgrade


thanks for the suggestions. I am concern because in a cisco link it is stated that "do not delete the system image that the router already uses".

What would be the consequences if I delete this image first and upload the new image after?

Cisco Employee

Re: 3845 software upgrade


the way i understand this is that the issue here is that the isr routers, aswell as 2600, 37xx ect dont have a bootflash. In other words if you delete the original image and for whatever reason before you were able to put a new image into flash you loose power or reload the router you end up in rommon without a bootable image.

The rommon has a helper utility called tftpdnld, this is from one of my lab routers, a 3825:

rommon 3 > tftpdnld

Missing or illegal ip address for variable IP_ADDRESS

Illegal IP address.

usage: tftpdnld [-hr]

Use this command for disaster recovery only to recover an image via TFTP.

Monitor variables are used to set up parameters for the transfer.

(Syntax: "VARIABLE_NAME=value" and use "set" to show current variables.) "ctrl-c" or "break" stops the transfer before flash erase begins.

The following variables are REQUIRED to be set for tftpdnld:

IP_ADDRESS: The IP address for this unit

IP_SUBNET_MASK: The subnet mask for this unit

DEFAULT_GATEWAY: The default gateway for this unit

TFTP_SERVER: The IP address of the server to fetch from

TFTP_FILE: The filename to fetch

The following variables are OPTIONAL:

GE_PORT: Ethernet port number for download, 0 or 1 (default=0)

TFTP_MEDIA_TYPE: Media select for GE_PORT=0, 0(Copper) or 1(Fiber) (default=0)

TFTP_VERBOSE: Print setting. 0=quiet, 1=progress(default), 2=verbose

TFTP_RETRY_COUNT: Retry count for ARP and TFTP (default=20)

TFTP_TIMEOUT: Overall timeout of operation in seconds (default=7200)

TFTP_CHECKSUM: Perform checksum test on image, 0=no, 1=yes (default=1)

TFTP_MACADDR: The MAC address for this unit

GE_SPEED_MODE: 0=10/hdx, 1=10/fdx, 2=100/hdx, 3=100/fdx, 4=1000/fdx,

5=Auto (default)

Command line options:

-h: this help screen

-r: do not write flash, load to DRAM only and launch image

rommon 4 >

I have used this many times in the lab and it works quite well. You need to setup the variables to your matching values and start it with

tftpdnld -r

That is a way to do recovery if everything else failed. So to speak a exit of last resort.

If your current image is 34 MByte and your new image is 34 Mbyte and your flash is 64 Mbyte than you have not much choice. You will have to erase the flash and then copy the new image and reboot.

If something goes wrong while you are doing this see above recovery method.

A high end router, 7200, 7500, cat6k... has a bootflash. And there you keep a helper image. i.e. a -boot- image which has a very limited capability but it always allows you to access the router and copy a new image to its appropriate flash.

If you want to sort of emulate this on a 38xx than you can copy a small image. I.e. -ipbase- as first image into flash. Off course you need to erase also whatever is in there currently.

That way you can then later copy the new 34 Mbyte image with the correct feature set as second image and then you have always something to fall back onto.

There seem to be also some smaller files in the flash nowadays. If there is anything else than the image file and you need to erase the flash, than always save these files first so that you can restore them if needed later on.



New Member

Re: 3845 software upgrade

Hello Matthias,

many thanks for the reply. I will try the hint with the small IOS image, the IP BASE is just 15MB so I believe I can upload this one first, so I will have both images (old and IP base). Then I can delete the old one (after backing it up) and upload the new enterprise ios. Then I can specify the image I want the router to start (or even delete the ip base).

Cisco Employee

Re: 3845 software upgrade

Hi Apostolos,

you probably already know this, but you can upgrade the flash capacity to 128 (or 256) if you really want to keep both images on flash. Having the extra space on flash can also come in handy as a place to store traces, etc. when troubleshooting problems.

- Ray

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