Last Updated:
Wednesday, 8 June 2022 By: Steve Warner

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Cisco IOS™

Cisco IOS upgrade HOWTO


Install Cisco's TFTP server on a PC in the same subnet as the router.

Cisco TFTP server
copy new image into the base directory found in view -> options from menu.

Default c:\program files\cisco systems\cisco tftp server\

In Example
TFTP Server
Routers Address

View current IOS image in flash

c1603#show flash

PCMCIA flash directory:
File  Length   Name/status
  1   1958626  c1600-sy-mz.112-19.P  
[1958692 bytes used, 138460 available, 2097152 total]
2048K bytes of processor board PCMCIA flash (Read/Write)

Copy current image to tftp server

c1603#copy flash tftp
Source filename []? c1600-sy-mz.112-19.P
Address or name of remote host []?
Destination filename [c1600-sy-mz.112-19.P]? 
1958626 bytes copied in 20.896 secs (97931 bytes/sec)

Copy image from tftp server to router

c1603#copy tftp flash     
Address or name of remote host []?
Source filename []? c1600-sy-mz-120-5.bin
Destination filename [c1600-sy-mz-120-5.bin]? 
Accessing tftp://
Erase flash: before copying? [confirm]
Erasing the flash filesystem will remove all files! Continue? [confirm]
Erasing device... eeeeeeeeeeeeeeee ...erased
Erase of flash: complete
Loading c1600-sy-mz_120-5.bin from (via Ethernet0): !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[OK - 2578950/5157888 bytes]

Verifying checksum...  OK (0x3E45)
2578950 bytes copied in 82.96 secs (31450 bytes/sec)

router reloads

The prompt should not look like c1603(boot)> if it doesn't then the upgrade process has failed.
Typing the command 'show flh-log' should show why.

Check Flash has correct CRC

c1603>show flash detailed

PCMCIA flash directory:
File  Length   Name/status
        addr      fcksum  ccksum
  1   2578950  c1600-sy-mz-120-5.bin  
        0x40      0x3E45  0x3E45
[2579016 bytes used, 5809592 available, 8388608 total]
8192K bytes of processor board PCMCIA flash (Read/Write)

Show IOS version information

c1603#show version
Cisco Internetwork Operating System Software 
IOS (tm) 1600 Software (C1600-SY-M), Version 12.0(5), RELEASE SOFTWARE (fc1)
Copyright (c) 1986-1999 by cisco Systems, Inc.
Compiled Tue 15-Jun-99 21:30 by phanguye
Image text-base: 0x02005000, data-base: 0x02511248

ROM: System Bootstrap, Version 11.1(12)XA, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1)

c1603 uptime is 1 day, 51 minutes
System restarted by reload at 00:41:22 GMT Sun Feb 11 2001
System image file is "flash:c1600-sy-mz_120-5.bin"

cisco 1603 (68360) processor (revision C) with 12288K/4096K bytes of memory.
Processor board ID 12345678, with hardware revision 00000000
Bridging software.
X.25 software, Version 3.0.0.
Basic Rate ISDN software, Version 1.1.
2 Ethernet/IEEE 802.3 interface(s)
1 ISDN Basic Rate interface(s)
System/IO memory with parity enabled 16384K bytes of DRAM on SIMM  (On Board Memory disabled)
System running from RAM
8K bytes of non-volatile configuration memory.
8192K bytes of processor board PCMCIA flash (Read/Write)

Configuration register is 0x2102 Top

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