Problem with error 01C9 - More than one Ethernet devices

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Revision as of 10:12, 16 February 2006 by Danage (Talk | contribs) (Affected Models)
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Problem Description

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

  WARNING
  01C9: More than one Ethernet devices are found. Remove one of them.
  Press <Esc> 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

Solution

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]

ATTENTION!
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.

Usage.

  • If you want to use this to remove the 1802 error, do not install your Atheros card yet.
  • 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.
  • Boot from the disc.
  • If you choose to remove the 1802 error, do so and shut down after pressing Ctrl-Alt-Del.
  • If not already present, install the Atheros card now and boot from the disc.
  • Choose not to apply the no-1802.
  • Select your Atheros card from the list. A WRONG SELECTION MAY CAUSE DAMAGE!
  • Shut down after pressing Ctrl-Alt-Del. Upon 'cold' reboot, the 01C9 should be gone.

Limitations

The patch does not seem to work with the Atheros AR5005GS chipset due to some kind of EEPROM write protection. This is done either through hardcoded write protection to certain areas of the EEPROM, thus making it impossible to be changed by software. Or the write-enable channel of the EEPROM is disactivated. Slight chance might be to program one of the chipsets' "General Purpose Input/Output" components to activate it. Yet this would only be possible if a GPIO is connected to the write-enable channel.

Affected Cards

  • Gigabyte GN-WIAG02 MiniPCI card (01C9 can only be bypassed by pressing <Esc>).