3640 stuck in rommon- checksum error

[cryptotech]

I'm a little green so I'm hoping someone here would be so kind as to throw me a lifeline.

I have a 3640 as part of my lab which had no problems for the first week or so.

One morning I came in and powered everything up and found the 3640 sitting in rommon.

Error : uncompressed image checksum is incorrect
software forced crash..etc..

One of the first things I did when I got this router was to do a copy flash tftp and save a backup.

I've been trying to xmodem the backup and still get the same checksum error- software forced crash.

I've tried xmodem -r, xmodem -c and just xmodem.
Tried the fast baud rate of 115200 and standard 9600.

Everytime just gives the same checksum error and crash.

rommon 3 > xmodem -c c3640-js-mz.124-19.bin
Do not start the sending program yet...
File size Checksum File name
32176096 bytes (0x1eaf7e0) 0xec27 c3640-js-mz.124-19.bin

WARNING: All existing data in flash will be lost!
Invoke this application only for disaster recovery.
Do you wish to continue? y/n [n]: y
Ready to receive file c3640-js-mz.124-19.bin ...
Erasing flash at 0x31fc0000 ---THIS PORTION TOOK 1.5 HOURS!
program flash location 0x31ea0000
Download Complete!
program load complete, entry point: 0x80008000, size: 0x1eaf618
Self decompressing the image : #################################################
################################################################################
############################## [OK]

Error : uncompressed image checksum is incorrect 0xC527DC5F
Expected a checksum of 0xC524720B

*** System received a Software forced crash ***
signal= 0x17, code= 0x9, context= 0x8000ec80
PC = 0x800080d4, Cause = 0x20, Status Reg = 0x3041f003
rommon 4 >

Is there any way to TFTP boot from rommon...There is no tftpdnld command for the 3640

Any suggestions would be appreciated, since I don't know how on earth im going to get another IOS for this thing..

thanks,

Josh

 

[volleyman]

you have a hardware issue my friend, try replacing the flash card.

given that its older hardware, not sure if it has the replaceable flash card sticking out of the front like 2800 series....

Zane D.
Systems Admin

 

[burtsbees]

It has both internal and CF. I have two 16MB SIMMs in mine, and they both together hold a 29MB IOS.

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!

 

[cryptotech]

It has two 16mb as well, which I beleive is the max.

The size of the IOS is 31.4 MB

At the 9600 speed xmodem takes about 10 hours...

So the general consensus is that the two SDRAM sticks need to be replaced?

This is causing the checksum errors?

 

[volleyman]

I don't know about replacing both, but I also don't know of a way to verify which one it is...but in fact you have a flash issue, bad spot on it somewhere. that checksum is checking to make sure the full amount of space is actually available, when it finds out that its not, it throws up that error.



Zane D.
Systems Admin

 

[burtsbees]

And it's not SDRAM---it's flash.

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!

 

[cryptotech]

Thank you both for your advice, I will try new flash and keep my fingers crossed.

Josh

 

[cryptotech]

I replaced the flash and the same thing is happening... Does anyone have any suggestions?

rommon 1 > xmodem -c c3640-js-mz.124-19.bin
Do not start the sending program yet...
device does not contain a valid magic number
dir: cannot open device "flash:"

WARNING: All existing data in flash will be lost!
Invoke this application only for disaster recovery.
Do you wish to continue? y/n [n]: y
Ready to receive file c3640-js-mz.124-19.bin ...
Erasing flash at 0x31fc0000
program flash location 0x31ea0000
Download Complete!
program load complete, entry point: 0x80008000, size: 0x1eaf618
Self decompressing the image : #################################################
################################################################################
############################## [OK]

Error : uncompressed image checksum is incorrect 0xC527DC5F
Expected a checksum of 0xC524720B

*** System received a Software forced crash ***
signal= 0x17, code= 0x9, context= 0x8000ec80
PC = 0x800080d4, Cause = 0x20, Status Reg = 0x3041f003
rommon 2 >

 

[cryptotech]

Something else I can't understand...Where is the downloaded image stored before being loaded into flash?

It can't be transferred to flash during xmodem, since the flash is erased after the transfer completes.

So where is this 31 MB IOS image being stored before being loaded into flash?
thanks again as always..

 

[burtsbees]

device does not contain a valid magic number

This usually means that the IOS is corrupt...sorry I missed it before.

Did you back it up?

/

tim@tim-laptop ~ $ sudo apt-get install windows
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package windows...Thank Goodness!

 

[cryptotech]

Yes, I did a copy flash tftp right after I bought it.

It ran fine for a about a week then had the crash.
At that time there was no magic number message, i'm guessing it happened this time because I just replaced the flash and there was nothing on it...
After the xmodem transfer and failed reload, I tried to boot again, this time nomagic number message.

It's always the checksum error before and after replacing the flash.

Will try to find an IOS for it, to eliminate that possibility.
Doesn't seem to be a cut and dry fix, I'll just keep trying different things until it works I guess.

 

[cryptotech]

Just wanted to post the final outcome.

The problem was the DRAM...I replaced all 4 32MB sticks and it came right up.

Used the -y option for xmodem at 115200 which cut the transfer time in half as opposed to using xmodem at 115200.

Thanks for the advice everyone,