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Trouble using Break Key sequence to access ROMmon on a Cisco Router

boclay
Cisco Employee
Cisco Employee

Use Space Bar to simulate Break Key Sequence

Read this article if you are trying to generate a Break Key Sequence to access ROMmon, and the Break Key sequence does NOT seem to make it to the router.

Today, I needed to access ROMmon on an IR1101 Industrial Router for password recovery. Unfortunately, the Break Key sequence was NOT making it to the router. I know the Break-Key sequence (Ctrl-Fn-B or Fn-B) on my Lenovo laptop works because I used it recently to break into a different router. That router has an RJ45 console port. The IR1101 has a USB mini console port, so my Lenovo laptop was using a different serial port driver when connecting to the IR1101.

The work-around was to “simulate” a Break Key by changing the baud rate of my connection in Putty to 1200 and pressing the space bar. I found this information in a very old post where the author mentions HyperTerm and using a PS/2 (Does anyone else besides me remember the PS/2?)

Here are the steps:
Complete these steps to simulate a break key sequence:

    Connect to the router with these terminal settings:

    1200 baud rate
    No parity
    8 data bits
    1 stop bit
    No flow control

    You no longer see any output on your screen, and this is normal.

    Power cycle (switch off and then on) the router and press the SPACEBAR for 10-15 seconds in order to generate a signal similar to the break sequence.

    Disconnect your terminal, and reconnect with a 9600 baud rate. You enter the ROM Monitor mode.

  

15 Replies 15

To conclude, problem sorted out, ISR1100-4GLTE loaded with IOS-XE 17.9.8, set to autonomous mode (i.e. can be set to controller-mode as well at rommon) and properly booting at confreg register 0x2102.

Thanks