4500-X启动到“511K bytes of non-volatile configuration memory”，无法继续？

在设备做了某些配置后，尤其是升级，重启设备后，发现设备在如下界面卡住，无法进一步进入CLI命令行。

Platform Manager: starting in standalone mode (active)

Restricted Rights Legend

Use, duplication, or disclosure by the Government is
subject to restrictions as set forth in subparagraph
(c) of the Commercial Computer Software - Restricted
Rights clause at FAR sec. 52.227-19 and subparagraph
(c) (1) (ii) of the Rights in Technical Data and Computer
Software clause at DFARS sec. 252.227-7013.

cisco Systems, Inc.
170 West Tasman Drive
San Jose, California 95134-1706

Cisco IOS Software, IOS-XE Software, Catalyst 4500 L3 Switch Software (cat4500e-UNIVERSAL-M), Version 03.06.05.E RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2016 by Cisco Systems, Inc.
Compiled Thu 02-Jun-16 05:08 by prod_rel_team

Cisco IOS-XE software, Copyright (c) 2005-2015 by cisco Systems, Inc.
All rights reserved. Certain components of Cisco IOS-XE software are
licensed under the GNU General Public License ("GPL") Version 2.0. The
software code licensed under GPL Version 2.0 is free software that comes
with ABSOLUTELY NO WARRANTY. You can redistribute and/or modify such
GPL code under the terms of GPL Version 2.0.
(http://www.gnu.org/licenses/gpl-2.0.html) For more details, see the
documentation or "License Notice" file accompanying the IOS-XE software,
or the applicable URL provided on the flyer accompanying the IOS-XE
software.

cisco WS-C4500X-16 (MPC8572) processor (revision 9) with 4194304K bytes of physical memory.
Processor board ID JAE1925XXXX
MPC8572 CPU at 1.5GHz, Cisco Catalyst 4500X
Last reset from PowerUp
1 Virtual Ethernet interface
16 Ten Gigabit Ethernet interfaces
511K bytes of non-volatile configuration memory.

有可能等待了很久都没有跳出“Press RETURN to get started!”，这个时候可以进入ROMMON，去修改寄存器值，忽略一下配置，进入设备。

重启设备后，在如下信息弹出时按Ctrl+C

************************************************************
* *
* Welcome to Rom Monitor for WS-C4500X-16 System. *
* Copyright (c) 2008-2014 by Cisco Systems, Inc. *
* All rights reserved. *
* *
************************************************************

Rom Monitor (P) Version 15.0(1r)SG11
CPU Rev: 2.2, Board Rev: 9, Board Type: 108
CPLD Mobat Rev: 2.0x549a.0x59a4
Chassis: WS-C4500X-16

MAC Address : e4-aa-5d-ac-0e-7f
Ip Address : Not set.
Netmask : Not set.
Gateway : Not set.
TftpServer : Not set.

Non-Redundant system or peer not running IOS
System Uplinks & Linecards have been reset!!

***** The system will autoboot in 5 seconds *****

Type control-C to prevent autobooting.

Autoboot cancelled......... please wait!!!

Autoboot cancelled......... please wait!!!

Management Ethernet Link Up: 1Gb Full Duplex
rommon 1 > [interrupt]

rommon 1 >

然后尝试修改忽略配置，寄存器值会变为0x2142

rommon 3 >confreg

Configuration Summary :
=> load rom after netboot fails
=> console baud: 9600
=> autoboot from: commands specified in 'BOOT' environment variable

do you wish to change the configuration? y/n [n]: y
enable "diagnostic mode"? y/n [n]:
enable "use net in IP bcast address"? y/n [n]:
disable "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]: y

change console baud rate? y/n [n]:

change the boot characteristics? y/n [n]: n

Configuration Summary :
=> load rom after netboot fails
=> ignore system config info
=> console baud: 9600
=> autoboot from: commands specified in 'BOOT' environment variable

do you wish to save this configuration? y/n [n]: y
You must reset or power cycle for new configuration to take effect

然后reset

Loading image !!!!!!!!!!!!!!!!

Checking digital signature....
[bootflash:/cat4500e-universalk9.SPA.03.04.05.SG.151-2.SG5.bin]
Digitally Signed Release Software with key version A

Rommon reg: 0x00084F80
Reset2Reg: 0x00004200
*

Image load status: 0x00000003
####
Radtrooper 065 controller 0x0481ADD2..0x049B696C Size:0x00661EDC Program Done!
##############
Linux version 2.6.24.4.3.70.k10 (abhakat@build-lnx-036) (gcc version 4.2.1 p7 (Cisco c4.2.1-p7)) #1 SMP Mon Nov 3 08:15:09 PST 2014
Starting System Services

diagsk10-post version 5.1.4.0

prod: WS-C4500X-16 part: 73-14786-06 serial: JAE1925XXXX

Power-on-self-test for Module 1: WS-C4500X-16

CPU Subsystem Tests ...
seeprom: Pass

Traffic: L3 Loopback ...
Test Results: Pass

Traffic: L2 Loopback ...

......

Platform Manager: starting in standalone mode (active)

Restricted Rights Legend

Use, duplication, or disclosure by the Government is
subject to restrictions as set forth in subparagraph
(c) of the Commercial Computer Software - Restricted
Rights clause at FAR sec. 52.227-19 and subparagraph
(c) (1) (ii) of the Rights in Technical Data and Computer
Software clause at DFARS sec. 252.227-7013.

cisco Systems, Inc.
170 West Tasman Drive
San Jose, California 95134-1706

Cisco IOS Software, IOS-XE Software, Catalyst 4500 L3 Switch Software (cat4500e-UNIVERSALK9-M), Version 03.08.08.E RELEASE SOFTWARE (fc3)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2019 by Cisco Systems, Inc.
Compiled Fri 15-Mar-19 16:22 by prod_rel_team

Cisco IOS-XE software, Copyright (c) 2005-2015 by cisco Systems, Inc.
All rights reserved. Certain components of Cisco IOS-XE software are
licensed under the GNU General Public License ("GPL") Version 2.0. The
software code licensed under GPL Version 2.0 is free software that comes
with ABSOLUTELY NO WARRANTY. You can redistribute and/or modify such
GPL code under the terms of GPL Version 2.0.
(http://www.gnu.org/licenses/gpl-2.0.html) For more details, see the
documentation or "License Notice" file accompanying the IOS-XE software,
or the applicable URL provided on the flyer accompanying the IOS-XE
software.

This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html

If you require further assistance please contact us by sending email to
export@cisco.com.

cisco WS-C4500X-16 (MPC8572) processor (revision 9) with 4194304K bytes of physical memory.
Processor board ID JAE1925XXXX
MPC8572 CPU at 1.5GHz, Cisco Catalyst 4500X
Last reset from PowerUp
1 Virtual Ethernet interface
16 Ten Gigabit Ethernet interfaces
511K bytes of non-volatile configuration memory.

Press RETURN to get started!

Switch>
Switch>
Switch>

后续再通过Switch(config)#config-register 0x2102去修改寄存器的值。