Cisco Systems OL-6426-02 manual Changing the Configuration Register Manually, Rommon 1 confreg

Appendix C ROM Monitor

Configuration Register

Configuration Register

The virtual configuration register is in nonvolatile RAM (NVRAM) and has the same functionality as other Cisco routers. You can view or modify the virtual configuration register from either the ROM monitor or the operating system software. Within the ROM monitor, you can change the configuration register by entering the register value in hexadecimal format, or by allowing the ROM monitor to prompt you for the setting of each bit.

Changing the Configuration Register Manually

To change the virtual configuration register from the ROM monitor manually, enter the confreg command, followed by the new value of the register in hexadecimal format, as shown in the following example:

rommon 1 > confreg 0x2101

You must reset or power cycle for new config to take effect rommon 2 >

The value is always interpreted as hexadecimal. The new virtual configuration register value is written into NVRAM but does not take effect until you reset or reboot the router.

Changing the Configuration Register Using Prompts

Entering the confreg command without an argument displays the contents of the virtual configuration register and a prompt to alter the contents by describing the meaning of each bit.

In either case, the new virtual configuration register value is written into NVRAM but does not take effect until you reset or reboot the router.

The following display shows an example of entering the confreg command:

rommon 7> confreg

Configuration Summary enabled are:

console baud: 9600

boot: the ROM Monitor

		do you	wish to change the configuration? y/n [n]:					y
		enable		“diagnostic mode”? y/n	[n]:	y
		enable		“use net in IP bcast address”? y/n			[n]:
		enable		“load rom after netboot fails”? y/n			[n]:
		enable		“use all zero broadcast”? y/n		[n]:
		enable		“break/abort has effect”? y/n		[n]:
		enable		“ignore system config info”?		y/n [n]:
		change	console baud rate? y/n		[n]:	y
		enter rate: 0 = 9600, 1 = 4800, 2 = 1200, 3					= 2400	[0]: 0
		change	the boot characteristics? y/n			[n]:	y
		enter to boot:
		0 = ROM Monitor
		1 = the boot helper image
		2-15 = boot system
[0]:				0
		Configuration Summary
		Cisco 1800 Series Integrated Services Routers (Fixed) Software Configuration Guide
	C-6							OL-6426-02