True. One can't flash radio or bootloaders w/ s-on [w/o a HTC official ota/signature at least]
The current radio installed though does have cdma and gsm bands though. A sim unlock and changing of networks [*#*#4636#*#* and select such] will probably get one working. The sim unlock though might not be too easy a task. For good measure, I'm supercid'ing mine as well.
I wrote somewhere that the original owner's manual noted intl calling available, but one would need call Sprint first [undoutedly they talked the few who did through sim unlocking and added an intl calling plan]
I'll reactivate my tmo sim soon and let you guys know how the sim unlock/supercid fares, but in the past, this is all one has needed [on other world phones]. So, anyway, we'll see
I did this via riff box; so, I mentioned I doubt it'll be easy for most. [I tried many other ways to beat emmc read/write protection before I resorted to usb-jtag reprogramming, none successfully though]
Rob