From extras/mcufriend_how_to.txt
17. If you do not have a standard Uno Shield, you can add a SPECIAL to the mcufriend_special.h
Edit mcufriend_shield.h: #define USE_SPECIAL
Edit mcufriend_special.h: e.g. #define USE_MEGA_16BIT_SHIELD
If your "special" is write-only, the library can not read the ID. It always returns 0xD3D3
Since it can't read the ID, you must force the ID e.g. tft.begin(0x1963);
David.