Cisco Cisco IOS Software Release 12.0(2a)T1 Guide D’Information
Router#
You have to change the configuration register value in order to configure the router or access server to
boot into Rxboot mode.
boot into Rxboot mode.
Check the current value of the configuration register. You can see it in the last line of the show
version command output. It is usually set to 0x2102 or 0x102. You will need this value for a later
step.
version command output. It is usually set to 0x2102 or 0x102. You will need this value for a later
step.
Change the configuration register to the value 0x2101. This will prepare the router to boot into
RXboot mode:
RXboot mode:
Router>enable
Password:
! −−− Enter the password here.
Router#
Router#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#config−register 0x2101
Router(config)#^Z
Router#
%SYS−5−CONFIG_I: Configured from console by console
!−−− It is not necessary to save the configuration here, as the
!−−− configuration register has already been changed in NVRAM.
Router#reload
Note: If you are connected through Telnet, the session is lost after the reload. Wait a few minutes and
try again. It is strongly recommended that you do not perform a Cisco IOS software upgrade remotely
since most disaster recovery procedures require you to be physically located where the router is
installed.
Restore the previous configuration register value for the next reload.
try again. It is strongly recommended that you do not perform a Cisco IOS software upgrade remotely
since most disaster recovery procedures require you to be physically located where the router is
installed.
Restore the previous configuration register value for the next reload.
Note: Do not save the configuration while the router is in boot mode. Avoid using the save commands
(write memory or copy running−config startup−config ), and answer no to any prompt that
suggests you save your current configuration. If you save the configuration while the router is in this
mode, the configuration can be partially or completely erased.
(write memory or copy running−config startup−config ), and answer no to any prompt that
suggests you save your current configuration. If you save the configuration while the router is in this
mode, the configuration can be partially or completely erased.
In the following commands, replace the **** with the configuration register value that you noted
down in the previous step:
down in the previous step:
Router(boot)>
Router(boot)>enable
Password:
Router(boot)#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(boot)(config)#config−register 0x****
Router(boot)(config)#^Z
Router(boot)#
Note: If you do not remember the value of the configuration register that was previously set, you can
use 0x2102 in this step.
use 0x2102 in this step.
4.
Verify that the TFTP server has IP connectivity to the router.
5.