diff --git a/libraries/SD/utility/FatStructs.h b/libraries/SD/utility/FatStructs.h
index f5bdaa594..8a2d9ebcc 100644
--- a/libraries/SD/utility/FatStructs.h
+++ b/libraries/SD/utility/FatStructs.h
@@ -90,7 +90,7 @@ struct partitionTable {
   uint32_t firstSector;
            /** Length of the partition, in blocks. */
   uint32_t totalSectors;
-};
+} __attribute__((packed));
 /** Type name for partitionTable */
 typedef struct partitionTable part_t;
 //------------------------------------------------------------------------------
@@ -114,7 +114,7 @@ struct masterBootRecord {
   uint8_t  mbrSig0;
            /** Second MBR signature byte. Must be 0XAA */
   uint8_t  mbrSig1;
-};
+} __attribute__((packed));
 /** Type name for masterBootRecord */
 typedef struct masterBootRecord mbr_t;
 //------------------------------------------------------------------------------
@@ -236,7 +236,7 @@ struct biosParmBlock {
            * should always set all of the bytes of this field to 0.
            */
   uint8_t  fat32Reserved[12];
-};
+} __attribute__((packed));
 /** Type name for biosParmBlock */
 typedef struct biosParmBlock bpb_t;
 //------------------------------------------------------------------------------
@@ -271,7 +271,7 @@ struct fat32BootSector {
   uint8_t  bootSectorSig0;
            /** must be 0XAA */
   uint8_t  bootSectorSig1;
-};
+} __attribute__((packed));
 //------------------------------------------------------------------------------
 // End Of Chain values for FAT entries
 /** FAT16 end of chain value used by Microsoft. */
@@ -366,7 +366,7 @@ struct directoryEntry {
   uint16_t firstClusterLow;
            /** 32-bit unsigned holding this file's size in bytes. */
   uint32_t fileSize;
-};
+} __attribute__((packed));
 //------------------------------------------------------------------------------
 // Definitions for directory entries
 //
diff --git a/libraries/SD/utility/Sd2Card.cpp b/libraries/SD/utility/Sd2Card.cpp
index 361cd0a06..9805833e4 100644
--- a/libraries/SD/utility/Sd2Card.cpp
+++ b/libraries/SD/utility/Sd2Card.cpp
@@ -17,20 +17,32 @@
  * along with the Arduino Sd2Card Library.  If not, see
  * <http://www.gnu.org/licenses/>.
  */
+#define USE_SPI_LIB
 #include <Arduino.h>
 #include "Sd2Card.h"
 //------------------------------------------------------------------------------
 #ifndef SOFTWARE_SPI
+#ifdef USE_SPI_LIB
+#include <SPI.h>
+#endif
 // functions for hardware SPI
 /** Send a byte to the card */
 static void spiSend(uint8_t b) {
+#ifndef USE_SPI_LIB
   SPDR = b;
   while (!(SPSR & (1 << SPIF)));
+#else
+  SPI.transfer(b);
+#endif
 }
 /** Receive a byte from the card */
 static  uint8_t spiRec(void) {
+#ifndef USE_SPI_LIB
   spiSend(0XFF);
   return SPDR;
+#else
+  return SPI.transfer(0xFF);
+#endif
 }
 #else  // SOFTWARE_SPI
 //------------------------------------------------------------------------------
@@ -220,11 +232,14 @@ uint8_t Sd2Card::init(uint8_t sckRateID, uint8_t chipSelectPin) {
   // set pin modes
   pinMode(chipSelectPin_, OUTPUT);
   chipSelectHigh();
+#ifndef USE_SPI_LIB
   pinMode(SPI_MISO_PIN, INPUT);
   pinMode(SPI_MOSI_PIN, OUTPUT);
   pinMode(SPI_SCK_PIN, OUTPUT);
+#endif
 
 #ifndef SOFTWARE_SPI
+#ifndef USE_SPI_LIB
   // SS must be in output mode even it is not chip select
   pinMode(SS_PIN, OUTPUT);
   digitalWrite(SS_PIN, HIGH); // disable any SPI device using hardware SS pin
@@ -232,7 +247,15 @@ uint8_t Sd2Card::init(uint8_t sckRateID, uint8_t chipSelectPin) {
   SPCR = (1 << SPE) | (1 << MSTR) | (1 << SPR1) | (1 << SPR0);
   // clear double speed
   SPSR &= ~(1 << SPI2X);
-#endif  // SOFTWARE_SPI
+#else // USE_SPI_LIB
+  SPI.begin();
+#ifdef SPI_CLOCK_DIV128
+    SPI.setClockDivider(SPI_CLOCK_DIV128);
+#else
+    SPI.setClockDivider(255);
+#endif
+#endif // USE_SPI_LIB
+#endif // SOFTWARE_SPI
 
   // must supply min of 74 clock cycles with CS high.
   for (uint8_t i = 0; i < 10; i++) spiSend(0XFF);
@@ -456,6 +479,7 @@ uint8_t Sd2Card::setSckRate(uint8_t sckRateID) {
     error(SD_CARD_ERROR_SCK_RATE);
     return false;
   }
+#ifndef USE_SPI_LIB
   // see avr processor datasheet for SPI register bit definitions
   if ((sckRateID & 1) || sckRateID == 6) {
     SPSR &= ~(1 << SPI2X);
@@ -465,6 +489,23 @@ uint8_t Sd2Card::setSckRate(uint8_t sckRateID) {
   SPCR &= ~((1 <<SPR1) | (1 << SPR0));
   SPCR |= (sckRateID & 4 ? (1 << SPR1) : 0)
     | (sckRateID & 2 ? (1 << SPR0) : 0);
+#else // USE_SPI_LIB
+  int v;
+#ifdef SPI_CLOCK_DIV128
+  switch (sckRateID) {
+    case 0: v=SPI_CLOCK_DIV2; break;
+    case 1: v=SPI_CLOCK_DIV4; break;
+    case 2: v=SPI_CLOCK_DIV8; break;
+    case 3: v=SPI_CLOCK_DIV16; break;
+    case 4: v=SPI_CLOCK_DIV32; break;
+    case 5: v=SPI_CLOCK_DIV64; break;
+    case 6: v=SPI_CLOCK_DIV128; break;
+  }
+#else // SPI_CLOCK_DIV128
+  v = 2 << sckRateID;
+#endif // SPI_CLOCK_DIV128
+  SPI.setClockDivider(v);
+#endif // USE_SPI_LIB
   return true;
 }
 //------------------------------------------------------------------------------
diff --git a/libraries/SD/utility/Sd2Card.h b/libraries/SD/utility/Sd2Card.h
index 73b46fb44..989d3d8bf 100644
--- a/libraries/SD/utility/Sd2Card.h
+++ b/libraries/SD/utility/Sd2Card.h
@@ -31,6 +31,11 @@ uint8_t const SPI_FULL_SPEED = 0;
 uint8_t const SPI_HALF_SPEED = 1;
 /** Set SCK rate to F_CPU/8. Sd2Card::setSckRate(). */
 uint8_t const SPI_QUARTER_SPEED = 2;
+/**
+ * USE_SPI_LIB: if set, use the SPI library bundled with Arduino IDE, otherwise
+ * run with a standalone driver for AVR.
+ */
+#define USE_SPI_LIB
 /**
  * Define MEGA_SOFT_SPI non-zero to use software SPI on Mega Arduinos.
  * Pins used are SS 10, MOSI 11, MISO 12, and SCK 13.
@@ -66,7 +71,9 @@ uint8_t const  SPI_MISO_PIN = MISO_PIN;
 /** SPI Clock pin */
 uint8_t const  SPI_SCK_PIN = SCK_PIN;
 /** optimize loops for hardware SPI */
+#ifndef USE_SPI_LIB
 #define OPTIMIZE_HARDWARE_SPI
+#endif
 
 #else  // SOFTWARE_SPI
 // define software SPI pins so Mega can use unmodified GPS Shield
diff --git a/libraries/SD/utility/Sd2PinMap.h b/libraries/SD/utility/Sd2PinMap.h
index 1c76dd3a4..02ad52f5f 100644
--- a/libraries/SD/utility/Sd2PinMap.h
+++ b/libraries/SD/utility/Sd2PinMap.h
@@ -17,6 +17,22 @@
  * along with the Arduino SdFat Library.  If not, see
  * <http://www.gnu.org/licenses/>.
  */
+#if defined(__arm__) // Arduino Due Board follows
+
+#ifndef Sd2PinMap_h
+#define Sd2PinMap_h
+
+#include <Arduino.h>
+
+uint8_t const SS_PIN = SS;
+uint8_t const MOSI_PIN = MOSI;
+uint8_t const MISO_PIN = MISO;
+uint8_t const SCK_PIN = SCK;
+
+#endif // Sd2PinMap_h
+
+#elif defined(__AVR__) // Other AVR based Boards follows
+
 // Warning this file was generated by a program.
 #ifndef Sd2PinMap_h
 #define Sd2PinMap_h
@@ -350,3 +366,7 @@ static inline __attribute__((always_inline))
   }
 }
 #endif  // Sd2PinMap_h
+
+#else
+#error Architecture or board not supported.
+#endif
diff --git a/libraries/SD/utility/SdFat.h b/libraries/SD/utility/SdFat.h
index 344326f98..89c244418 100644
--- a/libraries/SD/utility/SdFat.h
+++ b/libraries/SD/utility/SdFat.h
@@ -23,7 +23,9 @@
  * \file
  * SdFile and SdVolume classes
  */
+#ifdef __AVR__
 #include <avr/pgmspace.h>
+#endif
 #include "Sd2Card.h"
 #include "FatStructs.h"
 #include "Print.h"
@@ -286,8 +288,10 @@ class SdFile : public Print {
   size_t write(uint8_t b);
   size_t write(const void* buf, uint16_t nbyte);
   size_t write(const char* str);
+#ifdef __AVR__
   void write_P(PGM_P str);
   void writeln_P(PGM_P str);
+#endif
 //------------------------------------------------------------------------------
 #if ALLOW_DEPRECATED_FUNCTIONS
 // Deprecated functions  - suppress cpplint warnings with NOLINT comment
diff --git a/libraries/SD/utility/SdFatUtil.h b/libraries/SD/utility/SdFatUtil.h
index 7d6b4104f..d1b4d538f 100644
--- a/libraries/SD/utility/SdFatUtil.h
+++ b/libraries/SD/utility/SdFatUtil.h
@@ -24,12 +24,14 @@
  * Useful utility functions.
  */
 #include <Arduino.h>
+#ifdef __AVR__
 #include <avr/pgmspace.h>
 /** Store and print a string in flash memory.*/
 #define PgmPrint(x) SerialPrint_P(PSTR(x))
 /** Store and print a string in flash memory followed by a CR/LF.*/
 #define PgmPrintln(x) SerialPrintln_P(PSTR(x))
 /** Defined so doxygen works for function definitions. */
+#endif
 #define NOINLINE __attribute__((noinline,unused))
 #define UNUSEDOK __attribute__((unused))
 //------------------------------------------------------------------------------
@@ -49,6 +51,7 @@ static UNUSEDOK int FreeRam(void) {
   }
   return free_memory;
 }
+#ifdef __AVR__
 //------------------------------------------------------------------------------
 /**
  * %Print a string in flash memory to the serial port.
@@ -68,4 +71,5 @@ static NOINLINE void SerialPrintln_P(PGM_P str) {
   SerialPrint_P(str);
   Serial.println();
 }
+#endif  // __AVR__
 #endif  // #define SdFatUtil_h
diff --git a/libraries/SD/utility/SdFile.cpp b/libraries/SD/utility/SdFile.cpp
index e786f56bb..c19500e59 100644
--- a/libraries/SD/utility/SdFile.cpp
+++ b/libraries/SD/utility/SdFile.cpp
@@ -18,7 +18,9 @@
  * <http://www.gnu.org/licenses/>.
  */
 #include <SdFat.h>
+#ifdef __AVR__
 #include <avr/pgmspace.h>
+#endif
 #include <Arduino.h>
 //------------------------------------------------------------------------------
 // callback function for date/time
@@ -256,9 +258,15 @@ uint8_t SdFile::make83Name(const char* str, uint8_t* name) {
       i = 8;   // place for extension
     } else {
       // illegal FAT characters
-      PGM_P p = PSTR("|<>^+=?/[];,*\"\\");
       uint8_t b;
+#if defined(__AVR__)
+      PGM_P p = PSTR("|<>^+=?/[];,*\"\\");
       while ((b = pgm_read_byte(p++))) if (b == c) return false;
+#elif defined(__arm__)
+      const uint8_t valid[] = "|<>^+=?/[];,*\"\\";
+      const uint8_t *p = valid;
+      while ((b = *p++)) if (b == c) return false;
+#endif
       // check size and only allow ASCII printable characters
       if (i > n || c < 0X21 || c > 0X7E)return false;
       // only upper case allowed in 8.3 names - convert lower to upper
@@ -1232,6 +1240,7 @@ size_t SdFile::write(uint8_t b) {
 size_t SdFile::write(const char* str) {
   return write(str, strlen(str));
 }
+#ifdef __AVR__
 //------------------------------------------------------------------------------
 /**
  * Write a PROGMEM string to a file.
@@ -1251,3 +1260,4 @@ void SdFile::writeln_P(PGM_P str) {
   write_P(str);
   println();
 }
+#endif