Sdfatlib readData and readStart failing

Using Arduino Storage
2

The problem is myfile is not the object that can access the SD card.

You need to use sd.card() like this:

#include <SdFat.h>
SdFat sd;
SdFile file;
const int chipSelect = 10;
uint32_t bgnBlock;
uint32_t endBlock;
uint8_t bufferOne[512];
void setup() {
  Serial.begin(9600);
  if (!sd.init(SPI_FULL_SPEED, chipSelect)) sd.initErrorHalt();
  file.open("axelf.snd",O_READ);
  Serial.println(file.contiguousRange(&bgnBlock, &endBlock));
  Sd2Card *card = sd.card();
  Serial.println(card->readStart(bgnBlock));
  Serial.println(card->readData(bufferOne));
  for (uint8_t i = 0; i < 20; i++) {
  //  Serial.println(bufferOne[i], HEX);
  }
}
void loop() {}