Cisco IOS Recovery
c3750
Example Issue
- Issue: cannot boot, prompt is at switch:
<source lang=text>
- Example fail
switch: boot Loading "flash:/c3750-ipbasek9-mz.122-46.SE.bin"...flash:/c3750-ipbasek9-mz.122-46.SE.bin: no such file or directory
Error loading "flash:/c3750-ipbasek9-mz.122-46.SE.bin"
Interrupt within 5 seconds to abort boot process. Loading "flash:/c3750-ipbasek9-mz.122-55.SE6.bin"...@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ Error loading "flash:/c3750-ipbasek9-mz.122-55.SE6.bin"
Interrupt within 5 seconds to abort boot process. Boot process failed...
switch: dir flash </source>
- Switch: c3750
- IOS: c3750-ipbasek9-mz.122-55.SE1.bin
Requirements
- Have your .bin file stored locally (laptop)
- linux + minicom with working serial connection
Steps
- Connect to switch - minicom 9600 8N1
- CHANGE baud rate of switch (otherwise it will be hours to load a file)
<source lang=text>
set BAUD 115200
</source>
- change minicom to 115200 8N1
- ready switch to recieve file over xmodem
<source lang=text>
copy xmodem: flash:/<your IOS version filename>.bin
</source> <source>
- example
switch: copy xmodem: flash:/c3750-ipbasek9-mz.122-55.SE1.bin Begin the Xmodem or Xmodem-1K transfer now... C </source>
- send the local .bin file with minicom through xmodem
<source lang=text> ctrl-a z s xmodem select file (hit space) enter to send file </source>
- watch your .bin file load! It will still be slow, but not hours @ 9600
<source lang=text>
+-----------[xmodem upload - Press CTRL-C to quit]------------+
Press CTR|Sending c3750-ipbasek9-mz.122-55.SE1.bin, 94373 blocks: Give |
|your local XMODEM receive command now. |
.........|Xmodem sectors/kbytes sent: 54509/6813k | |
| |
| |
switch: | |
| |
switch: +-------------------------------------------------------------+ </source>
- set baud rate back to 9600
- otherwise you or someone else will be really confused when they next try to use it. Go back into the bootloader by power-cycling the switch and holding down the “Mode” button.
<source lang=text>
set BAUD 9600
</source>
- type boot (may have to type boot flash:/<your cisco file>.bin
<source lang=text>
switch: boot Loading "flash:/c3750-ipbasek9-mz.122-46.SE.bin"...flash:/c3750-ipbasek9-mz.122-46.SE.bin: no such file or directory
Error loading "flash:/c3750-ipbasek9-mz.122-46.SE.bin"
Interrupt within 5 seconds to abort boot process. Loading "flash:/c3750-ipbasek9-mz.122-55.SE1.bin"...@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ File "flash:/c3750-ipbasek9-mz.122-55.SE1.bin" uncompressed and installed, entry point: 0x1000000 executing...
Restricted Rights Legend
Use, duplication, or disclosure by the Government is subject to restrictions as set forth in subparagraph (c) of the Commercial Computer Software - Restricted Rights clause at FAR sec. 52.227-19 and subparagraph (c) (1) (ii) of the Rights in Technical Data and Computer Software clause at DFARS sec. 252.227-7013.
cisco Systems, Inc.
170 West Tasman Drive
San Jose, California 95134-1706
..... truncated </source>
- Check that you can reboot OK without ending up in the bootloader again.
Other Tricks
- If the switch is not going into the bootloader, you may be able to force it
- Try power-cycling the Catalyst while holding the “Mode” button on the front in to get the bootloader.
- file system needs to be initialzied
- Type “flash_init” to initialise the filesystem. (In our case, this wasn’t necessary)
- Type “load_helper” to load any helper files (in our case there weren’t any since we’d just wiped the flash).