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help, 3745 no ios

3745 router...

in rommon mode with no IOS

how do I get an IOS on there?




Re: help, 3745 no ios

You have a CF slot on 3745. Try to get the image into a CF card (you can use a CF card reader on your PC) and then boot from rommon off of the CF card.

Otherwise you are looking at xmodem or tftpdnld. I am not sure if tftpdnld is supported on a 3745. (I think it doesnt)

Community Member

Re: help, 3745 no ios

Recovering the System Image (tftpdnld): Example

rommon 16 > IP_ADDRESS=

rommon 17 > IP_SUBNET_MASK=

rommon 18 > DEFAULT_GATEWAY=

rommon 19 > TFTP_SERVER=

rommon 20 > TFTP_FILE=c2801-is-mz.113-2.0.3.Q

rommon 21 > tftpdnld

okay, we just did all that with different IP's of course... our own...

but when we type "tftpdnld" it says command not known or whatever....


(we dont have CF card)

oh, and we added the FE_PORT=1

we're using fe0/1


Community Member

Re: help, 3745 no ios


Someone found a CF card and we have the .bin file and it shows up in slot0:

we try the "boot slot0:nameofimage.bin" and it doesn't work...

is there a way to copy the image file from slot0: to flash: from the rommon?

Re: help, 3745 no ios

Ok, now that you have a CF card, lets try this.

a. rommon>dev

b. From the above output, see if it says slot0 or disk0 for your CF slots.

c. Based on that try to specify the following command

boot slot0:.bin or boot slot0: (with no bin extension)

boot disk0:.bin or boot disk0: (with no bin extension)

d. What error message do you get when you try to boot from the CF card ? Does it say cannot read from specified device ? If then its possible that the 3745 is not understanding the formating of the CF card. Probably it was formated in PC and hence the router is not able to read from it.

e. Now I am not sure if you can format a CF card from rommon. Lets hope it does. Once you format it in the router, (if possible) and then put the card back into the PC CF card reader, transfer the file and then go back to step c.

f. If step e does not work, then I dont have a clue other than trying to do it via rommon. I remember a while ago when i had to do rommon on 3745 and I didnt have an option to change the console port speed of the 3745. Hence this is what I did.

i. Downloaded an IP only image (12.0 or any image you can find which is smallest in size, I could find one with 6 MB size).

ii. Use 9600 baud (default rate) and do xmodem and copy the image into the router and boot from this image.

iii. Once you boot using this basic image, you can then use copy tftp flash command to upgrade the router to the required image.

Here is a link which explains rommon recovery using xmodem.

PS: For a 3745, You wont have to reset the jumper like said in the link.


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