CL6729 Based Adapter Fails "Code 12" in Windows 2000
On some Windows 2000 machines, notably ones with Intel 810/815/840 based motherboards and PCI to PCI bridges, Windows 2000 may fail to configure the PCMCIA adapter with a code 12 message. On some PC's this message will appear in the device manager and Windows will request a reboot; after this reboot Windows may fail with a blue screen message indicating the video driver failed to load. If Windows does not fail to boot then the device manager will show that the CL6729 device has failed to start, indicating an error "Code 12."
This problem is caused by a bug in Windows 2000; Windows treats the CL6729 controller as a 24-bit
device (even though it is capable of addressing 32-bit memory addresses) so all
resources for the adapter must reside below 1MB in the "upper memory" area
which usually has free memory blocks available, which Windows 2000 is not
able to find.
On system reboot, Windows grants the PCMCIA driver the request for memory (Windows grants the PCMCIA driver a block of video memory that is not available) before the video driver loads and makes it's requests for memory and hence the blue screen stop.