Int 2C Fn 0002  P - Rm386 V6.00 - Cloaking - Set Segment Base Address      [m]

   AX = 0002h
   SI = selector
   EBX = new physical base addres

Return: CF clear if successful
   CF set on error
       AX = error code (see AX=0000h)

Return: AX=0000h,AX=0003h,AX=0004h,INT 31/AX=0007h