Howto reslove IBM’s Problem with error 01C9 (More than one Ethernet devices) and 1802 Error

From ThinkWiki



Problem Description

Certain ThinkPads show a warning message during POST when a WLAN card with an Atheros chipset is present in the MiniPCI slot:

01C9: More than one Ethernet devices are found. Remove one of them.
Press  to continue.

At POST, the BIOS conducts a scan for ethernet devices. It does this by reading the “PCI Class Codes” of every connected device. If more than one ethernet device is found, it produces the 01C9 error message. Unlike other wireless cards, which identify themselves as “other” network adapters, Atheros classify themselves as “ethernet”. This collides with the internal ethernet controller (also a PCI device) and causes the 01C9 to appear.

Affected Models

Not affected are

  • ThinkPad T4x series
  • ThinkPad X4x series


The solution is to modify the Atheros EEPROM so that the card correctly identifies itself as an “other” instead of an “ethernet” network adapter. A Linux Live CD to do both this and remove the 1802 error message is now available. [1] (~ 4 MB).

This software was designed FOR ATHEROS CARDS ONLY. Even though most users confirm it working fine, it can potentially harm your computer. The authors are in no way to be held liable for damage caused by this program. There is no warranty given, either express or implied for any fitness for any kind of purpose. YOU AGREE TO USE THIS ENTIRELY AT YOUR OWN RISK.

Functionality. This patch changes the PCI Class ID from 0x0200 to 0x0280, which corresponds “network device: other”. It manipulates neither the PCI vendor ID nor the device ID. Therefore, functionality of drivers and operating systems will not be affected. Uninstalling drivers is not necessary before using this patch.


  1. Burn the .ISO file to a CD/DVD. Make sure to open the image instead of burning it as a regular file on the disc.
  2. If you want to remove the 01C9 error only, skip to step 8.
  3. To remove the 1802 error, make sure you do not have the Atheros card installed in the MiniPCI slot.
  4. Boot from the disc.
  5. Choose to remove the 1802 error.
  6. Shut down after pressing Ctrl-Alt-Del.
  7. (Physically) install the Atheros card now.
  8. Boot from the disc (again).
  9. Choose not to apply the no-1802.
  10. Select your Atheros card from the list. A WRONG SELECTION MAY CAUSE DAMAGE!
  11. Shut down after pressing Ctrl-Alt-Del. Upon ‘cold’ reboot, the 01C9 should be gone.


The patch does not seem to work with chipsets above AR5004x due to some kind of EEPROM write protection. This protection is either hardcoded into the EEPROM, thus making it impossible to be changed by software. Or the write-enable channel of the EEPROM has been disactivated. Slight chance might be to program one of the chipsets’ “General Purpose Input/Output” components to activate it. Yet this would require a GPIO’s output to be connected to the write-enable channel of the EEPROM (depends on the circuit board layout).

Affected cards

  • Gigabyte GN-WIAG02 MiniPCI card (AR5005GS chipset) (01C9 can only be bypassed by pressing ).
  • Senao NMP-8602 MiniPCI card (AR5006X chipset) (01C9 can only be bypassed by pressing ).
  • SparkLAN WMIA-166AG MiniPCI card (AR5006XS chipset (01C9 can only be bypassed by pressing ).

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