Cisco… what else…

CISCO IOS Recovery 3750X and 3560X with USB flash drive

Today i get a call from a customer that he had deleted the whole flash from his 3560X switch and when he restarted the switch it won’t come up… why? 😉

so i told him that without the .bin image on the flash it’s not possible that the switch will run…

What can i do?

You can do an IOS recovery… but not with the very slow xmodem  (i know you can tune it up to !WOW! 115kbps)… but nowadays with an USB flash drive…

Here you can see how it works:

NOTE: Not all USB flash drives are supported, hence my recommendation to get several ready.

1. USB pen drive max. 16GB format as FAT16
2. copy the .bin image onto the flash drive
3. disconnect the switch from power
4. connect the flash drive to the switch
5. hold the “mode” button on the switch, give power, hold the button until the SYST LED flashes only green fast and when it is green and stop flashing hold on 2 seconds and then leave the button, otherwise it will boot “normaly”  (takes about ca. 30-40 seconds)
6. switch: flash_init
7. …wait… (it could be that the switch will hang on —more— push enter and it will go on, try it)
8. switch: dir usbflash0:       !!check if the switch can read from USB
9. switch: copy usbflash0:IOS-IMAGE.bin flash: IOS-IMAGE .bin        !!copy the image from usb to flash
10. switch: boot flash: IOS-IMAGE .bin        !! with this command the switch boots up with the image immediately
11. conf t      !! enter to conf t
12. boot system flash:.bin      !! don’t forget to set the image as bootvar 😉
13. wr mem       !! and save it, so it will boot also when it get powered off 😉

I tried it also to recover the IOS image with TFTP via the management port… but it doesn’t worked for me… it get not up the management port, so i couldn’t copy the file from TFTP to FLASH…

[best regs]


2 responses to “CISCO IOS Recovery 3750X and 3560X with USB flash drive

  1. Richard Daltom February 25, 2013 at 22:00

    Dude, this process works and it saved me big time. I was attempting to copy the .bin file via the xmodem command and it was taking forever….only to bomb-out before it was successful. Formatting the usb drive to FAT (default) is required and my switch read the usb stick immediately. Thanks again

    • Andrei Marinus December 16, 2013 at 19:08

      OMG … I am so grateful for this … For the life of me I could not stop the booting process on the box. I put a wrong IOS and it was not recognized by the switch, as a consequence it continuously rebooted. No matter what PC and Windows version or Hyperterminal application I tried, it did not want to send the break sequence.
      Then I found this post. I worked like magic.
      Thank you !!!

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