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A Cisco 1600 series router does not run the Cisco IOS image, even though Flash and DRAM memory requirements are considered met


Core Issue

The Cisco 1600 series routers are produced in two versions: the 1600 and the 1600-R.

The Cisco 1600 series router images run from Flash, while the 1600-R series router images run from RAM. Therefore, these are the two different types of Cisco IOS  Software files available:

  • The run from the Flash Cisco IOS Software image is not compressed and can be identified by having -l (the letter L) in the filename. Since these images are uncompressed and run from Flash, they generally require more Flash and less RAM than the equivalent run from RAM image.
  • The run from RAM images are compressed and have -mz in the filename. Because the run from RAM image is stored in Flash in a compressed state, and decompresses into RAM at bootup, less Flash and more RAM is required.

Therefore, the Cisco 1600 series routers generally have insufficient RAM to run 1600-R images. If you were to add RAM to a Cisco 1600, it could run a Cisco 1600-R image.


If after loading a Cisco IOS Software image to Flash on a Cisco 1600 series router, the router fails to boot to the Cisco IOS Software with a memory error, perform these steps:

     1. Verify how much Flash and DRAM are installed on the router.

     2. ssue the show version command, as shown:

1600#show version
 Cisco Internetwork Operating System Software
 IOS (tm) 1600 Software (C1600-Y-M), Version 12.1(7), RELEASE SOFTWARE (fc1)
 Copyright (c) 1986-2001 by Cisco Systems, Inc.
 Compiled Thu 22-Feb-01 13:45 by kellythw
 Image text-base: 0x02005000, data-base: 0x025B766C
 ROM: System Bootstrap, Version 12.0(3)T, RELEASE SOFTWARE (fc1)
 ROM: 1600 Software (C1600-RBOOT-R), Version 12.0(3)T, RELEASE SOFTWARE(fc1)
1600 uptime is 4 minutes
 System returned to ROM by error - software forced crash, PC 0x2112FCC
 System restarted at 17:19:56 JST Sun Mar 16 2003
 System image file is "flash:c1600-y-mz.121-7.bin"
 Cisco 1603 (68360) processor (revision C) with 9216K/3072K bytes of memory.
 Processor board ID 27997266, with hardware revision 00000004
 Bridging software.
 X.25 software, Version 3.0.0.
 Basic Rate ISDN software, Version 1.1.
 1 Ethernet/IEEE 802.3 interface(s)
 1 Serial(sync/async) network interface(s)
 1 ISDN Basic Rate interface(s)
 System/IO memory with parity disabled
 8192K bytes of DRAM onboard 4096K bytes of DRAM on SIMM
 System running from RAM
 7K bytes of non-volatile configuration memory.
 4096K bytes of processor board PCMCIA Flash (Read/Write)
 Configuration register is 0x2102

This line shows that the router has 12 MB of DRAM (9216 K + 3072 K = 12288 K, or 12 MB):

Cisco 1603 (68360) processor (revision C) with 9216K/3072K bytes of memory

This line shows that the router has 4 MB of Flash:

4096K bytes of processor board PCMCIA Flash (Read/Write)

     3. Once the amount of installed Flash and DRAM have been determined, check the Flash and memory requirements for the Cisco IOS Software image being installed.

     4. Verify whether the image is a run from a Flash image (with a -l in the filename), or a run from the RAM image (with a -mz in the filename).

Note: When downloading images from Cisco Downloads, the run from Flash images are listed under 1601-1604. The run from RAM images are listed under 1601R-1605R. Selecting the correct type is critical because the memory requirements are different.

     5. If the router does not meet the memory requirements for the image, choose one of these options:

  • Use a different version that works with the currently installed memory.
  • Add RAM or Flash to the router.