Bitwise operation not working as expected (C using Gameboy development kit)

#include 
#define UINT8 unsigned char
UINT8 setNibble(UINT8 orig, UINT8 value) {
    UINT8 rtn = 0;
    rtn = (orig & 0b11110000) | (value & 0b00001111); //doesn't work, returns 0
    //rtn = (64 & 240) | (2 & 15);                      //works, basic values, returns a 66
    //rtn = (64 & 240) | (value & 15);                  //works, without orig, returns a 66
    //rtn = (orig & 240) | (value & 15);                //doesn't work, returns 64               
    //UINT8 mask  = (UINT8)0xF0;          //solution suggested by Stackoverflow AI
    //UINT8 low   = (UINT8)(value & 0x0F);
    //rtn = (UINT8)((orig & mask) | low);                 //doesn't work, returns a 2
    return rtn;
}
int main() {
    UINT8 num = setNibble(65,2); 
    printf("ORIG %02x\n", 65);
    printf("VALU %02x\n", 2);
    printf("RES  %02x\n", num);
    return 0;
}

generates what is expected

ORIG 41
VALU 02
RES  42

If you want both numbers to be under 0x10 (15 or less) then you have to shift one of them, as in

unsigned set_nibble(unsigned upper, unsigned lower)
{
    return ((upper & 0x0f)