Simple. Goto xda-developers.com, scroll down to the relative section in the forums, download the latest Dutty rom. He always packs the latest radio rom with his roms.
READ THE STICKY IN THE FORUM BEFORE YOU TRY TO FLASH IT. Sorry for the caps, but it will save a lot of effort later. You MUST flash the SPL file to your tytn 1st, but all of this is explained in the stickies.