From my own research, here is how to get the FM radio working. I don't understand it, but it works.
1. Download the file attached to this post:
http://xdaforums.com/showpost.php?p=41186240&postcount=15
2. Follow instructions for that file as outlined in this post
http://xdaforums.com/showpost.php?p=41769682&postcount=35
I suspect you didn't put it in the correct location.
You need to place it into the root, not the "sd card" folder (which appears as "0").
To do that;
1) go to settings in File Manager and changing from Safe Mode to Root
2) find the fminit.zip and tick it
3) go right up to the root folder where you'll find a data folder.
4) open that, then open the local folder within it. (Create a new folder by clicking the menu icon on screen. It looks like 2 parallel dotted lines in the bottom left)
5) Add userinit.d folder and open it
6) select Move Selected File here from the menu
7) select the zip file and go to the menu and Extract
8) open the folder that was created and select the fminit.d file and move it back into the userinit.d folder.
9) delete the empty fminit folder and zip file.
10) restart and try out SpiritFM.
3. Open up Terminal Emulator, and type this
su
[hit enter, then]
insmod /system/lib/modules/radio-iris-transport.ko:
4. Install Spirit.
Voila, radio works.
Having said all that, at the moment I need to do the insmos step after every reboot. Anyone know how to make it stick? Cheers