you do NOT need to testpoint. You CAN downgrade the Bootloader Firmware (Bootloader is NOT Baseband!) to 3.9 or 4.6 Fakeblank!
First downgrade iPhone Firmware to 1.4.4
then downgrade Bootloader to 3.9
then try to erase baseband
then try to flash a baseband (must not be unlocked) to get wifi back