How do I start my router in ROMmon mode?
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If your router gets stuck in ROMmon mode during the boot process, examine the value of the configuration register by entering the confreg command. Change the value of the configuration register as shown below to stop the router to go into the ROMmon mode after reloading.
How do I get my cisco router out of ROMmon mode?
How do I get my cisco router out of Rommon mode?

- Either switch off or shut down the router.
- Remove the compact flash that is on the rear of the router.
- Switch on the router.
- Once the router is on Rommon mode, reinsert the compact flash.
- Type confreg 0x2142 at the rommon 1> prompt in order to boot from Flash.
How do I switch to ROMmon mode?
Use a DB-9 connector on the PC, and a HyperTerminal connect window to connect to the Supervisor. Press Enter. If you get the rommon > prompt, skip to Step 3. If the switch continuously reboots, press Control-C to prevent autoboot and to get into ROMmon mode.
How do I enter ROMmon mode on a Cisco router 1941?
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.

How do I boot a Cisco router from USB in Rommon mode?
Power on the router and when it starts to boot up press the Break key to enter ROMMON mode. Once in ROMMON mode enter the following command to boot to USB: boot usbflash0: (e.g. boot usbflash0:1841-advsecurityk9-mz.
How do I change the configuration register on a Cisco router?
To change the configuration register settings from the Cisco IOS CLI, complete the following steps:
- Connect a terminal or PC to the router console port.
- Configure your terminal or terminal emulation software for 9600 baud (default), 8 data bits, no parity, and 2 stop bits.
- Power on the router.
What is Rommon mode in Cisco router?
The ROM Monitor (ROMMON) is a bootstrap program that initializes the hardware and boots the Cisco IOS XE software when you power on or reload a router. If your router does not find a valid system image to load when it is booting, the system enters the ROMMON mode.
How do you enter ROMmon mode on a Cisco router 1921?
Press break on the terminal keyboard within 1 minute of power up in order to the router into ROMmon. Enter in confreg 0x2142 at the rommon 1> prompot in order to boot the from Flash.
How do you enter ROMmon mode without a break key?
How to Simulate a Break Key Sequence
- Connect to the router with these terminal settings: 1200 baud rate.
- 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.