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IOS upgrade on a 3750 stack

Hi All,

We are planning to upgrade IOS on five 3750 stack switches.

The existing IOS is pretty old and has number of caveats.

It would be helpful if you take a moment to go through the attachment and suggest me necessary correction.



Regards Vinayak
Everyone's tags (1)

IOS upgrade on a 3750 stack

Hi Vinayak,

The attached doc is looks ok.
however you can do the ios upgrade automatically or manually. Whichever you prefer.
See the below nice link which will take you step by step.

Please rate the helpfull posts.

Cisco Employee

IOS upgrade on a 3750 stack

You can choose any of the IOS which suits your netowrk. Just make sure that all the 3750 should have same image running for the stack to come up successfully.

And as mentioned by Naidu, go through the link for step by step upgrade process.



Please rate useful posts.

Cisco Employee

IOS upgrade on a 3750 stack


From the document attached i see that we are running with a .tar image.

In order to delete the .tar image you should use the below command since it is a directory.

delete /force /recursive flash1:c3750-i9-mz.121-19.EA1d

The above applies for manual deletion of the old image from all the switches.

Otherwise we can use the automatic method. The steps would be,

archive download-sw /overwrite tftp://

Hope this helps.



pls rate this answer if you found this content was useful

Hello,I have one problem. I


I have one problem. I am upgrading three 3750V2 switches in stack.

Copied IOS on to master switch flash (flash 2) as switch 2 is master here.

Tried to copy IOS from flash2 to flash1 and flash 3, but could not do so due to space issues.

I know I have to overwrite the existing image. But, this would cause problem of switches not joining the stack after reboot.

I do not have any old IOS on flash1 and 3 to delete and make some space. I only have the current(running) IOS.

How do I upgrade the stack in this scenario? 

I am using c3750-ipbasek9-mz.150-2.SE6.bin image file.




Hello Raghav,Please follow

Hello Raghav,

Please follow the next steps to upgrade the entire stack:

1- Delete the old IOS from switches 1 and 3

switch#delete flash1:<old_image>

switch#delete flash3:<old_image>

2- Now we have enough space to upload the new code for the two members. So please upload the image into the flash

3- Verify the integrity of the new image

switch#verify flash:/<new_image>

4- Change the boot variable for the entire stack

switch(config)#boot system switch all flash:<new_image>

Note: If the above is not supported we may need to do it manually for each member

switch(config)#boot system flash1:<new_image>

switch(config)#boot system flash2:<new_image>

switch(config)#boot system flash3:<new_image>

5- For both cases we need to save the changes


6- Need to check that we have the correct boot statement on each switch

switch#show bootvar

In good theory we should see the new boot variable for each switch

7-We can reload the entire stack, after deleted old image, uploaded new one, verified the integrity of the IOS, corrected boot statement.














It worked. Thanks!

It worked. Thanks!


thanks u  sir for sharing

thanks u  sir for sharing this information


Re: thanks u  sir for sharing

Thank you all for the good comments. I have put some icing on the cake and modified the document to help further. Feel free to review and comment on it. Some highlights from my edit to the original document (thanks for the nice document):

1. Download the . tar image. Using the .tar image is a good practice  


2. IOS Image upgrade


Delete the old image and copy/extract the .tar file into all the switches flash file system. This way you can keep the .bin file into a separate directory as of now. But it is the best practice to disable the web server from the switch if you are not using it. Having the .bin file in a subdirectory has the advantage of allowing you to "delete *" and not blow away the ios image.  It's an easy way to get the switch back to factory default.



#archive download-sw /overwrite /imageonly /reload /no-version-check /allow-feature-upgrade tftp://


This command will delete your old image and put the new image in a separate directory as before and extract the .bin file from it. Will save time in deleting images from all switches separately and copy the new image back to all switches.


3. Configure the Boot Variable


You don’t have to reconfigure the flash boot variable but if you are using tftp as the second boot variable you need to reconfigure it.


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