Copying IOS to 3750 on 3825 backplane

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Sep 4th, 2008
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I have a 3825 with a 3750 switch module installed through the HIMI. The upgraded IOS was corrupt and the previous working one is deleted. I cannot transfer an IOS to the switch using xmodem, it keeps timing out, I believe do to retries. Is there a way to transfer from the router flash to the switch? Or another way to transfer to the switch in boot loader?

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graemeporter Thu, 09/04/2008 - 07:29
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Try putting an IOS image on a USB stick, and put the USB stick into the router. Reboot the router. It may boot from the usbflash0: drive.

If that doesn't work, connect a PC to your router's G0/0 port using a crossover cable. The PC should be running a TFTP server, and should have a copy of the IOS on it. You can use the "tftpdnld" command in ROMMON to download a copy of the image to the router over TFTP.

Before you can use "tftpdnld", you need to set a number of environment variables, which you do by copying and pasting the following :






Replace the x's with the filename of your IOS image. On your PC, set the IP address to, mask to, and gateway as

Then, on the router, type "tftpdnld" to begin the transfer.

Hope this helps!

Kind regards,


profit311 Thu, 09/04/2008 - 07:44
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Will the Switch see the USB ports when the Router restarts? I set the IPs in the switch, but "tftpdnld" will not work on the router, it is not in ROMMON, and it won't work on the switch, it is in load_helper mode.


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