Hacking cellular radio for increased network capabilities?

[Nandaly]

Here's the question / challenge.

Sprint/Verizon/Telus TP2 has both CDMA and GSM capability. Not sure about Sprint or Verizon, but Telus TP2 uses 2100MHz frequency for their 3G HSPA network. According to HTC, they indicate it uses the "CDMA side" of the phone for the 2100MHz, whereas GSM side only for quadband GSM world capability.

Question: Does the GSM side of this phone connect to higher capability network functionality, i.e., can you get onto GSM carriers HSPA or 3G/3G+ networks via SIM card (including in the US; understanding that an "unlocked" WU vs. WV radio is flashed)

Challenge : Is it possible to unlock further capabiltiy of GSM side to utilize the 2100MHz capability so that you can use 2100MHz HSPA networks through the GSM side.

Thoughts regarding this latter challenge: Is this something that is "programmed" via the SPL and has anyone ever dug into SPL hacking/programming (if so with what tools?), ... and also if you look at stock ROMS there is a GSM component in them (yes even in the CDMA carrier verisons), is it possible through this part of the ROM to "re-program" the GSM frequency band "usage".