11-4
Cisco CSR 1000V Series Cloud Services Router Software Configuration Guide
OL-27477-07
Chapter11 Accessing and Using GRUB Mode
Modifying the Configuration Register (confreg)
Note The modified configuration register value is automatically written into NVRAM, but the new value does
not take effect until you reset or power-cycle the router.
SUMMARY STEPS
1. confreg [value]
DETAILED STEPS
The following shows an example of entering GRUB mode and using the configuration register. You
access the GRUB mode by entering the Cisco IOS XE config-register command and specifying the
value as “0000”.
Router(config)# config-register 0x0000
GNU GRUB version 0.97 (638K lower / 3143616K upper memory)
[ Minimal BASH-like line editing is supported. For the first word, TAB
lists possible command completions. Anywhere else TAB lists the possible
completions of a device/filename. ESC at any time exits to menu. ]
grub> help
[ Minimal BASH-like line editing is supported. For the first word, TAB
lists possible command completions. Anywhere else TAB lists the possible
completions of a device/filename. ESC at any time exits to menu. ]
confreg [VALUE] help [--all] [PATTERN ...]
grub> confreg
Configuration Summary
(Virtual Configuration Register: 0x0)
enabled are:
boot: the boot loader
do you wish to change the configuration? y/n [n]:
ignore system config info? y/n [n]:
automatically boot default system image? y/n [n]:
Configuration Register: 0x0
grub> confreg
Configuration Summary
(Virtual Configuration Register: 0x0)
enabled are:
boot: the boot loader
Command or Action Purpose
Step1 confreg [value]
Example:
grub> confreg 0x2102
Changes the configuration register settings while in
GRUB command mode.
•Optionally, enter the new hexadecimal value for
the configuration register. The value range is
from 0x0 to 0xFFFF.
•If you do not enter the value, the router prompts
for each bit of the 16-bit configuration register.