Home Devices Cisco Switches software update copy to switch tip

Cisco Switches software update copy to switch tip


I was never able to get TFTP working. It may have simply been the Server I was trying to get working (Pumpkin)…but it kept saying the block size needed to be increased and eventually timed out trying. The Cisco supported block size from 512-8192, but when I changed it to 8192 and set the TFTP Server to 8192 it still didn’t work. From the Pumpkin website: “TFTP protocol by default operates on 512 bytes long blocks, counted using a 16 bits word. Which means that the file size is limited to 65536*512=32M. Although, if both sides supports it you can raise the limit by increasing the block size. For example, if you use 1024 bytes long blocks you can go as far as 64M.” The update .bin is ~512MB. It should work, but it did not.

At any rate, rather than keep trying TFTP Servers, the easiest thing for me was to use a USB Flash drive. 4GB, FAT formatted is best. Using the CLI:

  • Copy the bin to flash on the switch with copy usbflash0:<filename> flash:
  • Verify it’s there with dir flash:*.bin
  • Continue on with the installation instructions from the Release Notes.

Note: If the file fails to copy with an “error reading…” halt, then unplug the USB drive, wait a beat or two, plug it back in, then immediately start the copy again. Should work. If not then try a different USB drive. Also, if you don’t have a 4GB drive you can format any drive FAT and make a 4GB partition that you can put the update on.


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