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(Re)install an IOS operating system on a Cisco 2960 switch

Prereqs

  • a PC (BIOS/UEFI) running Linux Mint 21
  • minicom terminal emulation software
  • a tFTP service
  • a console cable
  • a Cisco 2960 24TT-L or 24TC-L Plus switch

IOS transfer over serial (xmodem)

From IOS

Verify that there is enough space left on the Flash filesystem.

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Switch#dir flash:
Directory of flash:/

    2  -rwx    15979136   Mar 1 1993 01:25:54 +00:00  c2960-lanbasek9-mz.152-7.E7.bin     <---- OLD image
    3  drwx         128   Mar 1 1993 00:06:45 +00:00  pnp-tech
    4  drwx           0   Mar 1 1993 00:01:03 +00:00  pnp-info
    5  -rwx        1048   Mar 1 1993 00:01:08 +00:00  multiple-fs

65544192 bytes total (49417728 bytes free)
Switch#

Set the baud rate to 115200 to speed up the transfer. You will lose the connection after the last command. Some gibberish characters can emerge.

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Switch#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Switch(config)#line con 0
Switch(config-line)#speed 115200
C�

Adjust the settings in your terminal emulation program to match the new baud rate. For minicom, press Ctrl+A and then Z. Type O and choose "Serial port setup". Change setting E and Enter twice. Exit.

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Switch#conf t                                                                                                    
Enter configuration commands, one per line.  End with CNTL/Z.                                                    
Swit+-----------------+---------[Comm Parameters]----------+----------------+                                    
Swit| A -    Serial De|                                    |                |                                    
C�  | B - Lockfile Loc|     Current:  9600 8N1             |                |                                    
    | C -   Callin Pro| Speed            Parity      Data  |                |                                    
    | D -  Callout Pro| A: <next>        L: None     S: 5  |                |                                    
    | E -    Bps/Par/B| B: <prev>        M: Even     T: 6  |                |                                    
    | F - Hardware Flo| C:   9600        N: Odd      U: 7  |                |                                    
    | G - Software Flo| D:  38400        O: Mark     V: 8  |                |                                    
    | H -     RS485 En| E: 115200        P: Space          |                |                                    
    | I -   RS485 Rts |                                    |                |                                    
    | J -  RS485 Rts A| Stopbits                           |                |                                    
    | K -  RS485 Rx Du| W: 1             Q: 8-N-1          |                |                                    
    | L -  RS485 Termi| X: 2             R: 7-E-1          |                |                                    
    | M - RS485 Delay |                                    |                |                                    
    | N - RS485 Delay |                                    |                |                                    
    |                 | Choice, or <Enter> to exit?        |                |                                    
    |    Change which +------------------------------------+                |                                    
    +-----------------------------------------------------------------------+

Press Enter The connection is back. Initiate an xMODEM transfer. Confirm the destination filename. The switch will then prompt you to start the transfer from your terminal emulator.

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    Switch(config-line)#end
    Switch#copy xmodem: flash:c2960-lanbasek9-mz.152-7.E8.bin
    Destination filename [c2960-lanbasek9-mz.152-7.E8.bin]?     <----- press ENTER
    Begin the Xmodem or Xmodem-1K transfer now...
    CCC

For minicom, press Ctrl+A and then Z. Type S (Send files) and select "xmodem". Navigate your way to the new IOS file (here /home/guru/Downloads). Press Space to tag the file and press "Okay" to send.

Grab a coffee. This can take a long time depending on the size of the IOS image. Wait for the transfer to complete and then press Enter to quit.

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Switch#conf t                                                                                                         
Enter configuration commands, one per line.  End with CNTL/Z.                                                         
Switch(config)#line con 0                                                                                             
Swit+----------------[xmodem upload - Press CTRL-C to quit]----------------+                                          
C�  |l XMODEM receive command now.                                         |                                          
Swit|Xmodem sectors/kbytes sent: 109625/13703kRetry 0: NAK on sector       |                                          
Swit|Bytes Sent:15979776   BPS:8950                                        |                                          
*Mar|                                                                      |                                          
Swit|Transfer complete                                                     |                                          
Dest|                                                                      |                                          
Begi| READY: press any key to continue...                                  |                                          
CCC +----------------------------------------------------------------------+

Make the switch boot from the newly transferred IOS image, verify and reboot.

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Switch(config)#boot system flash:/c2960-lanbasek9-mz.152-7.E8.bin
Switch(config)#end
Switch#show boot
BOOT path-list      : flash:/c2960-lanbasek9-mz.152-7.E8.bin
...
...

Switch#reload

System configuration has been modified. Save? [yes/no]: no  <----- if asked
Proceed with reload? [confirm]

You have to adjust the settings in your terminal emulation program again, to match the default baud of 9600. Verify that the correct IOS image is loaded.

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Switch#show version
Cisco IOS Software, C2960 Software (C2960-LANBASEK9-M), Version 15.2(7)E8, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2023 by Cisco Systems, Inc.
...
...
System returned to ROM by power-on
System image file is "flash:/c2960-lanbasek9-mz.152-7.E8.bin"
Last reload reason: Reload command
...
...
Switch Ports Model                     SW Version            SW Image                 
------ ----- -----                     ----------            ----------               
*    1 26    WS-C2960+24TC-L           15.2(7)E8             C2960-LANBASEK9-M
...
...

If all went well, it's save to remove the old IOS image (if existing). Enjoy your new IOS!

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Switch#delete flash:c2960-lanbasek9-mz.152-7.E7.bin
Delete filename [c2960-lanbasek9-mz.152-7.E7.bin]? 
Delete flash:/c2960-lanbasek9-mz.152-7.E7.bin? [confirm]

Switch#dir flash:
Directory of flash:/

2  -rwx    15979672   Mar 1 1993 00:25:20 +00:00  c2960-lanbasek9-mz.152-7.E8.bin
3  drwx         128   Mar 1 1993 00:01:37 +00:00  pnp-tech
4  drwx           0   Mar 1 1993 00:01:03 +00:00  pnp-info
5  -rwx        1048   Mar 1 1993 00:01:08 +00:00  multiple-fs

65544192 bytes total (49461248 bytes free)

Switch#dir nvram:
Directory of nvram:/

65  -rw-           0                    <no date>  startup-config
66  ----           0                    <no date>  private-config
67  -rw-           0                    <no date>  underlying-config
 1  ----          71                    <no date>  persistent-data

65536 bytes total (64460 bytes free)

From ROMMON

First, start the switch in ROMMON-mode.

Initialize Flash manually.

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switch: flash_init
Initializing Flash...
flashfs[0]: 1 files, 1 directories
flashfs[0]: 0 orphaned files, 0 orphaned directories
flashfs[0]: Total bytes: 65544192
flashfs[0]: Bytes used: 3584
flashfs[0]: Bytes available: 65540608
flashfs[0]: flashfs fsck took 18 seconds.
...done Initializing Flash.

switch:

Verify that there is enough space left on the Flash filesystem.

Set the baud rate to 115200 to speed up the transfer. You will lose the connection after the last command. Some gibberish characters can emerge.

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switch: set BAUD 115200
                   �

Adjust the settings in your terminal emulation program to match the new baud rate. For minicom, press Ctrl+A and then Z. Type O and choose "Serial port setup". Change setting E and Enter twice. Exit.

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swit+-----------------+---------[Comm Parameters]----------+----------------+                                    
swit| A -    Serial De|                                    |                |                                    
C�  | B - Lockfile Loc|     Current:  9600 8N1             |                |                                    
    | C -   Callin Pro| Speed            Parity      Data  |                |                                    
    | D -  Callout Pro| A: <next>        L: None     S: 5  |                |                                    
    | E -    Bps/Par/B| B: <prev>        M: Even     T: 6  |                |                                    
    | F - Hardware Flo| C:   9600        N: Odd      U: 7  |                |                                    
    | G - Software Flo| D:  38400        O: Mark     V: 8  |                |                                    
    | H -     RS485 En| E: 115200        P: Space          |                |                                    
    | I -   RS485 Rts |                                    |                |                                    
    | J -  RS485 Rts A| Stopbits                           |                |                                    
    | K -  RS485 Rx Du| W: 1             Q: 8-N-1          |                |                                    
    | L -  RS485 Termi| X: 2             R: 7-E-1          |                |                                    
    | M - RS485 Delay |                                    |                |                                    
    | N - RS485 Delay |                                    |                |                                    
    |                 | Choice, or <Enter> to exit?        |                |                                    
    |    Change which +------------------------------------+                |                                    
    +-----------------------------------------------------------------------+

Press Enter The connection is back. Initiate an xMODEM transfer. The switch will then prompt you to start the transfer from your terminal emulator.

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switch: copy xmodem: flash:c2960-lanbasek9-mz.152-7.E8.bin                                                            
Begin the Xmodem or Xmodem-1K transfer now...                                                                         
CCC

For minicom, press Ctrl+A and then Z. Type S (Send files) and select "xmodem". Navigate your way to the new IOS file (here /home/guru/Downloads). Press Space to tag the file and press "Okay" to send.

Grab a coffee. This can take a long time depending on the size of the IOS image. Wait for the transfer to complete and then press Enter to quit.

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switch: copy xmodem: flash:c2960-lanbasek9-mz.152-7.E8.bin                                                                                                    
Begin the Xmodem or Xmodem-1K transfer now...                                                                                                                 
CCC +----------------[xmodem upload - Press CTRL-C to quit]----------------+                                                                                  
    |Sending c2960-lanbasek9-mz.152-7.E8.bin, 124841 blocks: Give your loca|                                                                                  
    |l XMODEM receive command now.                                         |                                                                                  
    |Bytes Sent:15979776   BPS:9379                                        |                                                                                  
    |                                                                      |                                                                                  
    |Transfer complete                                                     |                                                                                  
    |                                                                      |                                                                                  
    | READY: press any key to continue...                                  |                                                                                  
    +----------------------------------------------------------------------+

Update the BOOT parameter to match the new IOS.

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Switch: set BOOT flash:c2960-lanbasek9-mz.152-7.E8.bin
Switch:

Set the BAUD rate back to the default (9600 bps). You have to adjust the settings in your terminal emulation program again. Press Enter The connection is back.

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switch: unset BAUD                                                                                                                                            
                }                                                                                                                                           

switch:

Finally, boot the switch manually.

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switch: boot                                                                                                                                                  
Loading "flash:c2960-lanbasek9-mz.152-7.E8.bin"...@@@@@@@@@@@@@@@@@

Verify that the correct IOS image is loaded. Enjoy your new IOS!

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Switch#show version
Cisco IOS Software, C2960 Software (C2960-LANBASEK9-M), Version 15.2(7)E8, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2023 by Cisco Systems, Inc.
...
...
System returned to ROM by power-on
System image file is "flash:/c2960-lanbasek9-mz.152-7.E8.bin"
Last reload reason: Reload command
...
...
Switch Ports Model                     SW Version            SW Image                 
------ ----- -----                     ----------            ----------               
*    1 26    WS-C2960+24TC-L           15.2(7)E8             C2960-LANBASEK9-M
...
...

IOS transfer over network protocol (tFTP)

Transfer using a network protocol is only possible from IOS, not from ROMMON-mode.

tFTP

Install a tFTP service on the LAB-PC. Copy a valid Cisco IOS image file to the tFTP directory where files are served from. Adjust permissions.

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<TODO COPY AND PERMISSIONS>
guru@pc:~$ ls -lh /srv/tftp/
total 31M
-rw-r--r-- 1 root root 16M May 17 13:14 c2960-lanbasek9-mz.152-7.E7.bin
-rw-r--r-- 1 root root 16M May 17 13:14 c2960-lanbasek9-mz.152-7.E8.bin
guru@pc:~$

Configure an IP address and subnet mask on the switch. Verify.

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Switch#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Switch(config)#int vlan 1
Switch(config-if)#ip add 192.168.1.86 255.255.255.0
Switch(config-if)#no shut
Switch(config-if)#do show ip int br
Interface              IP-Address      OK? Method Status                Protocol
Vlan1                  192.168.1.86    YES manual up                    up      
...

Optional (in this case): ensure that the TFTP session is sourced from the correct interface (here: VLAN 1).

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Switch(config-if)#exit
Switch(config)#ip tftp source-interface vlan 1
Switch(config)#end
Switch#

Copy the IOS image from the TFTP server to the switch's flash memory.

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Switch#copy tftp://192.168.1.101/c2960-lanbasek9-mz.152-7.E8.bin flash:
Destination filename [c2960-lanbasek9-mz.152-7.E8.bin]?     <----- press ENTER
Accessing tftp://192.168.1.101/c2960-lanbasek9-mz.152-7.E8.bin...
Loading c2960-lanbasek9-mz.152-7.E8.bin from 192.168.1.101 (via Vlan1): !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[OK - 15979672 bytes]

15979672 bytes copied in 217.886 secs (73340 bytes/sec)
Switch#

Make the switch boot from the newly transferred IOS image, verify and reboot.

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Switch#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Switch(config)#boot system flash:/c2960-lanbasek9-mz.152-7.E8.bin
Switch(config)#end
Switch#show boot
BOOT path-list      : flash:/c2960-lanbasek9-mz.152-7.E8.bin
...
...

Switch#reload

System configuration has been modified. Save? [yes/no]: no  <----- if asked
Proceed with reload? [confirm]

If all went well, it's save to remove the old IOS image. Enjoy your new IOS!

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Switch#delete flash:c2960-lanbasek9-mz.152-7.E7.bin
Delete filename [c2960-lanbasek9-mz.152-7.E7.bin]? 
Delete flash:/c2960-lanbasek9-mz.152-7.E7.bin? [confirm]

Switch#dir flash:
Directory of flash:/

2  -rwx    15979672   Mar 1 1993 00:25:20 +00:00  c2960-lanbasek9-mz.152-7.E8.bin
3  drwx         128   Mar 1 1993 00:01:37 +00:00  pnp-tech
4  drwx           0   Mar 1 1993 00:01:03 +00:00  pnp-info
5  -rwx        1048   Mar 1 1993 00:01:08 +00:00  multiple-fs

65544192 bytes total (49461248 bytes free)

Switch#dir nvram:
Directory of nvram:/

65  -rw-           0                    <no date>  startup-config
66  ----           0                    <no date>  private-config
67  -rw-           0                    <no date>  underlying-config
 1  ----          71                    <no date>  persistent-data

65536 bytes total (64460 bytes free)

SSH (sFTP)

HTTP