sass86oh

The problem you're experiencing is because of the AirPortBrcmNIC.kext file that's present inside of IO80211Family.kext in /S/L/E. This kext file attempts to load when the card is detected and the system won't allow it because the kext file is designed to work under certain Mac computers provided that the device id and vendor id match Apples stock card with the same identifier of 14e4:43a0. That number is indeed a stock Apple configuration for Broadcom chipsets however its not exclusive to Apples particular hardware. The number that the Mac attempts to verify is the sub vendor/id which would be 106b:0131. That identifier is an exclusive means of verifying that the device is actually approved Apple hardware. There are ways to get the DW1820a working but the only method that's even remotely an option is removing the AirPortBrcmNIC.kext file and replacing it with the AirPortBrcm4360.kext from OS X 10.10 Yosemite. That particular kext does not have the same security measures programmed by Apple in order to prevent the end user from throwing different hardware in their old computers as opposed to going out and buying a new Mac which is what they want you to do. It's pretty dirty. The OS X Yosemite kext is the only one I've been able to get working. Every other version beyond Yosemite either won't load the driver or if it does the system will freeze up after 20 minutes or so. Prior to Yosemite this card didn't exist so its Broadcom Identifier is not present in AirPort kexts. If you remove the NIC kext you'll be able to boot the computer with the DW1820a in and then you can install the BRCM4360 kext followed by repairing the kext permissions and rebuilding the kextcache and then restart and it will work