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3620 IOS upgrade problem


I need some help. I have a 3620 and it had IOS image 12.3(17a) IP Feature set. I got 12.3(17b) Enterprise plus to upgrade.

The router has 64MB DRAM and 16MB of Flash. I copied the first IOS image over to my TFTP server (just incase). Then I copied over the newer IOS image from the tftp server to my router. The image copied over fine (all !'s) and the checksum was fine (displayed a OK).

Then when I rebooted the router is wont boot up. I uncompresses the image and displays a (OK) after all the ### characters. BUT here is my problem. It then says "error: uncompressed check sum incorrect" or something to that affect. Then it tries to load via the two external flash slots. After that is goes into Rommon 1> mode.

It could be the image or the flash module. Dont think it would be the flash module. How do I put the previous IOS image back on the router via the rommon mode to get this router working again???

Thank you guy and girls in advance!!



Well, I did a little lookin around on cisco site and found this link

Is this what I need to do?


Ok, just an update.

I used the Xmodem methond and got the previous working IOS back on it. Now I am thinking that the flash module is bad. Because the current image is only 8MB and the one im trying to load is 15MB and I have a 16MB flash module. Maybe there is a bad spot in the flash.

Hi Scott,

It does seem to point to the flash. I do have a suggestion, though - now that you've got the router back up, why don't you try to boot off that new image via TFTP. That way, you won't have to copy it to flash, but you do get to verify that the image is okay.

Hope that helps - pls rate the post if it does.


Thank you pkhatri,

Can you advise me as to the best way to boot from TFTP? what commands so on?

Thank you again

Firstly, set up a TFTP server on a PC/host that you can get to from the router. To make things easier, ensure that the image is stored on the root of the TFTP filesystem.

Then, enter in the following commands on the router:

boot system tftp:

Save the config and then re-load the router.

The procedure is pretty safe - if the router cannot boot using TFTP for some reason, it will fall back to the image in Flash.

Hope that helps - pls rate the post if it does.



I already have a TFTP server setup for use with my CCNP studies. And it can reach the TFTP server. The ethernet of the router and the TFTP server are connected to a 2950.

I take it that the boot system tftp command is a global config command? Do I have to setup a ip host statement mapping the word TFTP to the ip of the TFTP Server?

Thanks again

That was a typo. It should read:

boot system tftp ://

e.g boot system tftp


On some platforms, I find that you need to specify it as such:

boot system tftp://

You'll have to see which one works for you.


Sorry for the confusion. I just logged into a 3620 and it requires the following syntax:

boot system tftp

Hopefully that should do it :-)


Don't worry, no confusion.

I will try that here in about 30 minutes or so and report back

Thanks again!!

Ok, so far not so good.

Like I said earlier I got 12.3(17a) back on and working great.

then I added boot system tftp and saved the config and reloaded.

When it reload I get bumped back to Rommon 1> mode.

here is a snip from my running and startup config

no service password-encryption


hostname BBR1



boot system tftp c3620-j1s3-mz.123-17b.bin




Here is a part of the output of what happenes when I reload the router after the boot command is added.

Smart Init is enabled

smart init is sizing iomem


000037 0X00056400 Combination Single Ethernet 2 WAN

0X00098670 public buffer pools

0X00211000 public particle pools


If any of the above Memory Requirements are

"UNKNOWN", you may be using an unsupported

configuration or there is a software problem and

system operation may be compromised.

Rounded IOMEM up to: 3Mb.

adjusted iome size up to minimum size of: 0X00400000

Using 6 percent iomem. [4Mb/64Mb]

System Bootstrap, Version 11.1(19)AA, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1)

Copyright (c) 1998 by cisco Systems, Inc.

C3600 processor with 65536 Kbytes of main memory

Main memory is configured to 32 bit mode with parity disabled

rommon 1 >

Here is my show version also if that helps

Cisco Internetwork Operating System Software

IOS (tm) 3600 Software (C3620-I-M), Version 12.3(17a), RELEASE SOFTWARE (fc2)

Technical Support:

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

Compiled Mon 12-Dec-05 21:59 by evmiller

Image text-base: 0x60008B00, data-base: 0x60CE6000

ROM: System Bootstrap, Version 11.1(19)AA, EARLY DEPLOYMENT RELEASE SOFTWARE (fc


ROM: 3600 Software (C3620-I-M), Version 12.3(17a), RELEASE SOFTWARE (fc2)

Router uptime is 0 minutes

System returned to ROM by reload

System image file is "flash:c3620-i-mz.123-17a.bin"

cisco 3620 (R4700) processor (revision 0x81) with 61440K/4096K bytes of memory.

Processor board ID 07964447

R4700 CPU at 80MHz, Implementation 33, Rev 1.0

Bridging software.

X.25 software, Version 3.0.0.

1 Ethernet/IEEE 802.3 interface(s)

2 Serial network interface(s)

DRAM configuration is 32 bits wide with parity disabled.

29K bytes of non-volatile configuration memory.

16384K bytes of processor board System flash (Read/Write)

Configuration register is 0x2102

Hmm.... do you get any messages about problems getting to the TFTP server ?

Is the TFTP server on a directly connected segment or do you have to route to get to it ?


I have all my other devices turned off. All I have on is my PC/TFTP server and the router and they are both plugged into ports on one of my 2950's and are both in VLAN 1. I can ping the TFTP server with the router and vise versa. it loads fine with the 12.3(17a) image. Then when I add the boot system command it boots to the rommon prompt.

Then I have to do

confreg 0x2142 and reload without the config and erase the config and reload to a new empty config and it boots fine back to the 12.3(17a) image

Wierd huh