which one?
Digi-Key

You will have to tell us a bit more.

What do you mean by "them"? Do you mean that you cannot find the FireWire chips for sale anywhere? What is the part number of these devices?

What exactly was upside down when you plugged it in?

What type of computer and what type of FireWire port were you using (4-pin, 6-pin etc)? Do other devices work using the same computer FireWire port? Does the 8pre still fail on another computer?

My reading of this is that you inserted the (6 pin) firewire connector into a port at the back the wrong way up. It must have taken some effort but if you succeeded it is entirely possible that you have damaged more than just the connector as the 6 pin firewire also carries power.

First things first though, if my assumption is right, you will need to at least change the connector(s) but first I would try the firewire port of your PC (or mac) with some other device to make sure that end is not damaged. What Boswell suggested about another computer may work but you should very carefully inspect the 8pre ports for any bits of bent metal or broken plastic. If any damage is evident or you can no longer plug a good Firewire cable in then I'd suggest you do not apply power before replacing the connectors!

I guess that MOTU may still be using their own Xilinx FPGA design for Firewire and if so it is entirely possible that the Firewire power connections could have fried the Xilinx. That will not be so easy to replace and I would recommend finding a good service person or return the unit to MOTU for repair.

sorry about not being specific.

MrEase's assumption is right, I did plug the 6 pin firewire connector wrong way up. I tested my mac's 9 pin firewire output with my friends motu 8pre and it works fine.
The Motu 8pre has two firewire ports and either one of them work or look damaged. (I only plugged the cable in wrong side up to the first one).

I'm just going to assume that the Xilinx is fried, and throw the white flag in and take it to someone who knows what they are doing.

Thanks for the advice!

Well I was only speculating about the Xilinx as my original 828 has one! However whatever is inside could have been damaged by the power being presented to the wrong pins.

If you're not familiar with soldering surface mount (and this could be in a BGA package) then I'd certainly get it to a known good service tech who has all the right gear - not all do!