I did replace my old-fashioned IBM ThinkPad R50 wireless miniPCI network card with a new 802.11n device. Unfortunately, the BIOS did not really like it… Error 1802 Unathorized network card… As you might guess, there are work arounds. Some have posted how to add the new card to the list of accepted ones (patch some BIOS bytes) and some have posted how to flip the correct BIOS byte to disable the check.
I feared the effort to create a new BIOS and flash it to the ROM. Moreover, a BIOS updated would just obsolete my changes. However, there is a pretty cool bootable DOS CDROM that includes a patch
1) download and burn ISO here
2) disable your laptops wireless device (so the BIOS does not complain with Err 1802)
3) boot from disc
4) type no-1802 at the command prompt (there will be no message, don’t worry)
5) reboot, enable wireless device
Worked out of the box.