Problem with error 01C9 - More than one Ethernet devices
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:
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 remove both this and the 1802 error message is now available. [1]
Functionality This patch changes the PCI Class ID from 0x0200 to 0x0280, which corresponds "Network Device: Other". It manipulates neither the PCI vendor nor the device ID. Therefore, functionality of neither drivers nor operating systems will be affected.
Usage
- If you want to use this to remove the 1802 error, do not install your Atheros card yet.
- Burn the ISO to a CD or DVD. Make sure to open the image instead of burning it as a regular file on the disc.
- Boot from the CD.
- If you choose to remove the 1802 error, do so and reboot with Ctrl-Alt-Del.
- If not already present, install the Atheros card now and boot from the CD.
- Choose not to apply the no-1802.
- Select your Atheros card from the list. A WRONG SELECTION MAY CAUSE DAMAGE!
- Reboot by pressing Ctrl-Alt-Del, the 01C9 should be gone.