I am getting "no firewire ports found" error...

I freshy installed Snow Leopard 10.6.8 on a mid 2010 macbook pro. I did this after it had been upraded to Yosemite and the firewire port was not working. i have tried resetting pram and every other thing that has been suggested.

the closest discussion to my problem is thisAfter 10.6.2 update, 'No FireWire ports were found'

i do not have access to previous kext files to replace the ones on this machine now whcih fixed that users problems, has anyone else encountered this problem and know a fix? or has access to previous kext files?

the firewire port still sends power, as when i plug in an external it flashes for a split second and starts spinning up, it is just not recognized by the computer.

Mid 2010 Macbook Pro 7,1

2.4GHz Intel Core 2 Duo

4gb 1067 MHz DDR2