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c2800 router shows rubbish script when initializing rommon mode, please help

qutaibaahmed
Level 1
Level 1

Hi, I'm Qutaiba and I'm new to Cisco routers. I've got a c2800 router and it was stuck in rommon# mode,

Briefly! 

My c2800 shows rubbish script when initializing rommon mode as below and attached screen shots, after I changed the Buad rate 

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Details!

I tried many different ways to recover it but I found that either the image was corrupted, or the CF itself, I wasn't sure, I don't have another CF to check, so I got the Image c2800nm-ipbase-mz.151-3.T4.bin and loaded it in a USB flash to recover using it as a boot flash, it didn't work since when I insert the USB flash into its port of the router it shows nothing.

then I tried to use a TFTP server using tftpd32 to load the image into the router and didn't get any results as well. I did the steps in this video on youtube ( https://youtu.be/a-R-4zlbAV4)

between the steps is changing the Buad rate to 115200, so I did, after this it said to reset or power cycle the router so I entered the command reset and it resulted in a rubbish scripts appeared on the screen and lasts like for along time, so I power cycled it and it still gives me this rubbish script.

I tried to ctrl+break it but got nothing else than more of this rubbish every time I press any key it gives me more rubbish (as shown in the attached screen shots,  

*I used PuTTy, Hterm and TeraTerm to connect to the router each on a time".

*I used a serial cable attached to a UC232A adapter to connect it to my pc.

*I tried another laptop with a console serial port without the UC232A and even removed the CF of the router and it still gives me more rubbish each time I press any key

 

Kindly advice me what to do to fix this router

Qutaiba

 

11 Replies 11

Mark Malone
VIP Alumni
VIP Alumni

Hi

is the console giving any standard output if its completely corrupted you may have a serious issue and have to RMA it ?

The output in 1 of your screenshots suggests a an IOS software crash but the fact your console is now not working could be hardware

Illegal opcode

Cause: IOS software failure

Solution: 1st step is to upgrade the IOS software to the last version, verify if the crash still happens and if so, open a TAC case.

Thanks Mark, my friend

How do I check if the console giving any standard output if its completely corrupted?

Did you mean the Console port of the router or the cable?

and how  to upgrade the IOS software to the last version if the router is already not responding to anything just giving the rubbish script? even if I press any key, Ctrl+B,Ctrl+break and Alt+B, it still gives me more rubbish!

Sorry I'm new so could you explain a little bit detailed?

thanks again

 

Baud rate should be 9600 for a 2800 router, if you set it to that do you get a normal rommon>  output after reloading the router ?

https://supportforums.cisco.com/document/9096/garbage-output-seen-console-port

If all outputs are gone corrupted the router may need to be RMA'd , if console activity does not work theirs no real way to fix it

Verify your cabling and connections by connecting to another Cisco device just in case something has gone on the cabling

You will not be able to upgrade the software while the console is corrupted as the switch had previously gone into rommon> so telnet or ssh access will not be available, if you cannot get a proper response from the console port but your connections work fine on another device it will need to be repaired/replaced

 

 

Indeed I don't get normal rommon> output after reloading the router.

yes all outputs are gone corrupted

Verified cabling and connections by connecting to another Cisco device 1751 and it works properly

so I guess I'm going with the replacement and repairing

but one thing's left I need to understand, why would changing the Baud rate cause corruption to the rommon output and damage the console?

Thanks my Friend

Yes its not looking good checking output 4 again i see a TLB Fetch failure thats hardware fault , i dont think you  changing the baud caused it as 115200 is valid Cisco baud setting and having the wrong baud rate would not effect the device itself it would just not display any output,there is a team in Cisco that can tell you what happened exactly but it has to be sent off to be tested(takes months) and it depends on your support we had it done with a 7k nexus device the ASIC went haywire , general frontline TAC will just replace that though as theres 2 main errors showing in your outputs and the consoles not working

https://supportforums.cisco.com/document/14336/router-continuously-reloads-and-tlb-loadfetch-exception-and-system-received-bus-error

Alright, my friend Mark,

Thank you for your time and support, I appreciate.

Qutaiba

Did you pull the Compact Flash to see if rommon gives you any usable text?  If it does, you can try a TFTP boot.

Dude do this:
Verify if your other serial settings are the following:
 

Parity: None     
Data Bits: 8       bits
Stop Bit: 1         bits
Flow ctrl: None
 
For the BAUD rate, try to cycle through the following rates:
1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200

See if any of it responds


Lastly, if you can access the rommon try to type: "unset BAUD"   -case sensitive
this will reset to default the BAUD value to 9600


PS: Why did you change your BAUD rate? It should NOT be changed to avoid issues 

Additionally, if you did change your BAUD rate, you should set your terminal software's BAUD rate to match that

BAUD rate change is typically only done when doing firmware recovery specially on switches, but with newer models, recovery through the USB port is already supported.


 

This discussion has been reposted from Additional Communities to the Other Network Infrastructure Subjects community.

saif musa
Level 4
Level 4

Change the baud rate to its default value 9600, rubbish on the console - usually a baud rate mismatch

Dear Saif

I tried to change the baud rate to the default (from the emulator settings) but still gives the same rubbish, and I tried the other baud rates but still the same!

 

Thanks dear