;   digitalWrite(LED, HIGH ^ LEDinv);  f = SD.open((char*)filename, O_READ);  if (f) {   if (f.seek(fpos)) {    for (i = 0; i < BlkSZ; ++i)     dmabuf[i] = 0x0a;    bytesread = f.read(&dmabuf[0], BlkSZ);    if (bytesread) {     for (i = 0; i < BlkSZ; ++i)      _RamWrite(dmaAddr + i, dmabuf[i]);    }    result = bytesread ? 0x00 : 0x00;   } else {    