Here is a post I made over xda dev.com.
Ok, for all sprint users that are stuck because you loaded a cooked rom without loading the correct radio first. Or you have some how overwritten the radio rom, dont ask me how I did it but i did.
Here it the fix!
I was running the 2.40 Olipro boot loader when I preformed these steps. I do not know if they will work with other boot loaders.
download the Official 3.25 rom from HTC.
ftp://Mogulrom:sprinttitan@files164....CS_AM_Ship.exe
Use winrar to unpackages it.
Format a microsd card as FAT32.
Copy Special_4350.nbh, and RUU_signed.nbh from the unpackaged 3.25 rom to the freshly FAT32 formated microsd. Rename "Special_4350.nbh" to "TITA100.nhb. Rename "RUU_signed.nbh" to "TITAIMG.nbh". Inset the microsd. Put device in bootloader mode, press and hold both power, and camera then softreset while holding the buttons. Follow on screen instruction from boot loader mode.
Hope this helps...