Cisco 3750x – Update Firmware from TFTP

The last way I want to upgrade firmware is through the Serial port, even changing the baud rate to the highest possible takes forever to transfer an image, what I like to do is either hook my laptop via Ethernet to the switch directly and give the switch and laptop each an IP address on the same network so they I can transfer an image via TFTP, or give the switch an IP on my network (behind a firewall of course) and transfer the image via TFTP that way. Either way will work as long as the switch and your computer running a TFTP server can ping this will work.

You will need to have a TFTP server installed on your laptop/workstation any TFTP server you know how to configure and use will work.

Once the TFTP server on your computer is running and you have the firmware you wish to load available to the TFTP service, go on the switch issue the following command

This starts the copy of the firmware from your computer to the flash of your switch. After the copy is complete issue a ‘show flash’ command or ‘show flash#’ (# being the flash number 1-9 if its part of a stack) and you should have an output similar to below

Most of the time since when showing the flash the new firmware shows in the list above the old firmware a simple reboot will boot to the new firmware, but there are times where you will need to explicitly set the boot image which you can do with the following command.

At this point reboot the switch and watch on the console port, and you will see the switch boot to the new firmware image, and if it is required upgrade the microcode, which if it does keep in mind it kicks all the fans up to 100% and will take around 10 minutes to complete. Once it fully boots issue a ‘show switch’ command to view the current firmware version.

Note you can delete the existing image prior to the reboot and cause the switch to be forced to use the new firmware, although if there is an issue with the firmware you uploaded and it cant boot, it will have nothing to revert back to. From what I have experienced the majority of the time there is space on flash for 2 images at a time so as long as you remove the old firmware after you have confirmed you can boot to the new firmware you should be fine.

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