Update

[RWAP]

Suggest updating read_byte_from_file() as per master to improve speed - see v1.6.3 master code

int read_byte_from_file (char *xd)
{
    // This needs to be written to read each byte from specified file
    *xd=fgetc(inputFile);

    switch (msbsetting) {
        case 0:
            // No change
            break;
        case 1:
            // MSB setting clears bit 7
            xd = (int) xd & 127;
            break;
        case 2:
            // MSB setting forces bit 7 to 1
            xd = (int) xd | 128;
            break;
    }
    return feof(inputFile) ? 0 : -1;
}