My HTC Desire HD is still original version 2.3.5 (bootloader: LOCKED, S-ON and not Rooted).
When I dial a number, it opens the screen calls it "call in progress" then 2 seconds after it cut "End Call".
However, the 3G connection works.
The board is faulty?
I made the boot factory => still the same problem.
I flashed the same ROM RUU => still the same problem (RUU_Ace_Sense30_S_HTC_WWE_3.12.405.1_Radio_12.65. 60.29_26.14.04.28_M_release_225512_signed.exe).