The bootloader is no longer active in any way, shape, or form when the ROM is running - so it is 100% certain that what you are experiencing is not due to the S-OFF bootloader. A ROM could (in principle) be responsible for that behavior, but I sort of doubt that, too.
If you used the "root" PB00IMG.zip install to get S-OFF, then it flashed an older radio firmware to the phone (v2.40.00.01.22). I suppose that could cause trouble, but I'm sort of skeptical of that, too. You might want to try a PRL update first (*228 option 2 iirc) before worrying about the radio.
If you want to try the most recent radio, look for a file called "2.42.02.10.29.zip" over on XDA. It might be in the Hero CDMA (Sprint) forum. I can't remember where I found it. You flash it just like you flash a ROM, using the Amon_RA custom recovery. (You can flash it over any ROM, it won't touch anything but the radio firmware)
good luck
erisuser1