Switch won't take new IOS in ROMMON

[Jthnusmc]

Hi

Recently my team and I were trying to update the IOS on catalyst 3750 and 3850 switches and they ran into the problem of the switches not taking the IOS at all. We even tried using xmodem and somehow it made them worse. Now the switches are showing scribbles, as in letters, symbols and numbers all mixed up. We tried using the usb boot up way but the switches won't take the IOS as well.

We're not sure if that's fixable or not.

[Leo Laohoo]

Console into the switch and reboot.
Post the entire boot-up process so we can determine what is going on.

[Jthnusmc]

sorry for the inconvenience, because we had the switches sent to other team to fix so I can't give you exactly what happened but I can only give you what I remember when it finishes booting:

switch: set

ln34^fgfghj436S%$75oi88$#%tHru56TSh54o89j(JOjour tjoJIGo4j3y9 JFOKYPTU9&*pie978277H&3$%^&*{:>kdfGFDSP:>Llfghjh;><KJfGJHKl;@#$%%^&5=--9dsfojhithsb&*()8343mfdsh&^y349u98hv3y5*^55688hgj1dc"{?";er5Gh68hS1246Dfry54N6 ery586

switch: dir

     xmodem[0]: (read-only)

             null[1]: (read-write)

               bs[3]: (read-only)

         flash[18]: (read-only)

           tftp[19]: (read-write)

switch:

I tried setting the baud rate to 9600 or 115200 but every time it's always like this...and this happens after I used the xmodem to load the IOS

[balaji.bandi]

what kind of terminal software you using ? is this fixed after loading IOS?

[Leo Laohoo]

That is not a BAUD issue.
The issue is with the console terminal.
Try using a different computer.

[Jthnusmc]

We tried TeraTerm, Putty and SecureCrt

And we tried using different thumb drives and sometimes the switches can't even read them

when they're able to read the thumb drives and we tried to upload the IOS or boot from it it'll show 

Loading usbflash0:(IOS name) bad file number

or

usbflash0: contains unexpected values in partition table or boot sector

for now using the thumb drives is the only way we can think of to load the IOS

[Leo Laohoo]

Cisco appliances are very "sensitive" to generic (non-Cisco branded) thumb drives.

[Justin S]

Is the thumb drive over 4GB? Because that can cause issues

[Leo Laohoo]

---

@Justin S wrote:

Is the thumb drive over 4GB? Because that can cause issues

---

Not necessarily true.  
I have a Samsung 16Gb thumb drive and it works well with routers and switches (including supervisor cards).

[Jthnusmc]

Thank you Leo, Justin and bandi for all the responses

We've tried using 4GB, 8GB, 16GB and 32GB thumb drives and none of them works. At the end what made the switches to take the IOS was a 32GB sd card in a card reader.
even though the switches were able to take the IOS, a new problem came up: the switches are able to boot the IOS but won't stay that way everytime they reload
when the switches reloads they automatically goes back into ROMMON and the scribbles are still there. what's worse is that all the environment variables are gone, completely gone. We tried to paste in some of the "possible to be the same" environment variables ie. boot setup, baud rate etc.
even after all that process and reload, the switches goes automatically back to ROMMON and still stay that way

At this point should I just send them back to the factory and ask for new ones or keep troubleshooting???

[balaji.bandi]

here is the steps to fix.

1. From ROMMON - Boot from your 32GB SD CARD.

2. Once boot proces completed. and you have # prompt in cisco device.

3. Copy the cisco image from 32GB SD Card to flash :

4. Delete if any old image in the flash : , issue dir flash: show you old .bin image file

    you want to delete - delete flash:image.bin (example)

5. check the boot parameter by issuing -  show boot

  copy boot variable and remove the boot variable by issue command below

  no  boot system:oldimage.bin

  setup a new boot image

  boot system flash:newimage.bin

  write

  check again make sure boot image correct show boot.

  if all good.

6. reload the switch.

7. now the switch should boot automatically with new image.

if not - connect the console and post complete boot process to understand

Good luck.