How to Recover Cisco 3750 Firmware to a Working State?

Restore a corrupt Cisco 3750 IOS or Internetwork Operating System image by transferring a new image to flash storage using the Xmodem protocol. Power anomalies such as brown outs and surges can cause irreparable IOS image corruption. You should delete and replace a corrupt IOS image to ensure that the Cisco 3750 remains reliable. Access “switch:” mode through a serial connection and recover Cisco 3750 firmware to a working state

 

Things you’ll need to recover firmware Cisco 3750 switch

Windows 7 computer that has a serial COM port and the Tera Term program installed

Cisco serial console cable

IOS image for the Cisco 3750 switch stored on the Windows 7 computer

How to Recover Cisco 3750 Firmware to a Working State?

1. Connect the Cisco serial console cable 9 pin connector to the Windows 7 computer serial COM port. Plug the other end of the serial cable into the Cisco 3750 “Console” port.

2. Launch the Tera Term terminal console program and click “File” then “New connection.” Click the “Serial” radio button. Click the “Port” box and then the name of the serial COM port connected to the Cisco 3750 switch. Click the “OK” button.

3. Unplug the Cisco 3750 switch power cable. Press and hold down the “Mode” button located on the Cisco 3750 front left panel. Power up the Cisco 3750 switch and release the “Mode” button when the Port 1x light turns off.

4. Click the Tera Term window and press the “Enter” key two times. Type “flash_init” at the command prompt and tap “Enter.” Write “load_helper” at the command prompt and press “Enter.”

5. Type “dir flash:” on the command line and press “Enter.” View the command line output and note any files that end with “.bin” or directories that have “3750” in the name.

6. Type “dir flash:directory-name” at the command line. Replace “directory-name” with the name of a directory that has “3750” in the name and press “Enter.” Inspect the command line output and note any files that end with “.bin.”

7. Type “delete flash:image-file-name” at the command prompt. Replace “image-file-name” with the name of the “.bin” file noted earlier. Press the “Enter” key. Tap the “Y” key when prompted to confirm deletion and press “Enter.”

8. Click the “File” menu in the“Tera Term VT” window and then “Transfer.” Click “Xmodem” and then “Send.” Browse to and click on the new Cisco 3750 IOS image file and press “Enter.” Wait for the file transfer to complete (approximately 20 minutes).

9. Type “boot flash” at the command prompt and press “Enter” to boot the Cisco 3750 with the new image.

More Related Cisco 3750 tips:

How to Add a DHCP Range to a Cisco 3750 Switch?

How to Configure a Cisco 3750