Unable to write mem on 871W

Answered Question
Nov 3rd, 2009
User Badges:

Working some basic configs on a Cisco 871W that looked like had never been out of the box. (Did buy it on ebay). That said, just doing some basic config and testing it is not keeping the config that has been done. Just doing a simple change hostname and did both wr mem as well as copy running-config startup-config and it shows build and says ok but still when doing a reload for testing it resorts back to the default settings. Anyone give any suggestions on this?

Correct Answer by George Thomas about 7 years 7 months ago

Please check the config-register is set to 0x2102.

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (1 ratings)
Correct Answer
George Thomas Tue, 11/03/2009 - 19:15
User Badges:
  • Blue, 1500 points or more

Please check the config-register is set to 0x2102.

spcannady Wed, 11/04/2009 - 02:33
User Badges:

Appreciate your feedback on that. I noticed that it was not set to that when I did some troubleshooting. I figured out how to change it to the correct setting. It seems to have resolved the issue. Appreciate your insight on the matter. Can you take a moment to explain what exactly that is and why it would have been that way fresh out of the box?

spcannady Wed, 11/04/2009 - 02:24
User Badges:

Router#sho ver

Cisco IOS Software, C870 Software (C870-ADVSECURITYK9-M), Version 12.3(8)YI1, RE LEASE SOFTWARE (fc1)

Synched to technology version 12.3(10.3)T2

Technical Support: http://www.cisco.com/techsupport

Copyright (c) 1986-2005 by Cisco Systems, Inc.

Compiled Fri 22-Apr-05 14:57 by ealyon

ROM: System Bootstrap, Version 12.3(8r)YI, RELEASE SOFTWARE

ROM: Cisco IOS Software, C870 Software (C870-ADVSECURITYK9-M), Version 12.3(8)YI 1, RELEASE SOFTWARE (fc1)

Router uptime is 10 hours, 3 minutes

System returned to ROM by reload

System image file is "flash:c870-advsecurityk9-mz.123-8.YI1.bin"

Last reload reason: Reload command

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:


If you require further assistance please contact us by sending email to

[email protected].

Cisco 871W (MPC8272) processor (revision 0x100) with 236544K/25600K bytes of mem ory.

Processor board ID FHK094012GQ

MPC8272 CPU Rev: Part Number 0xC, Mask Number 0x10

5 FastEthernet interfaces

1 802.11 Radio

128K bytes of non-volatile configuration memory.

24576K bytes of processor board System flash (Intel Strataflash)

Configuration register is 0x2142

George Thomas Wed, 11/04/2009 - 07:41
User Badges:
  • Blue, 1500 points or more

The config-register is modified to do a password recovery. When its set to 0x2142, each time you reload therouter it just cleans up the config. After we get a fresh config, we boot into and set a new password and copy the config over. After this is done, we have to change the config-register to 0x2102 so that it retains the config even after the device is reloaded.

Hope this helps!!

spcannady Wed, 11/04/2009 - 15:15
User Badges:

The information you provided to me helped tremendously. I appreciate you taking the time to first provide insight to the problem and also give the reason it was doing what it did. Thank you very much!



This Discussion