diff --git a/MFRC522.cpp b/MFRC522.cpp
index b745d58..8b20c0c 100644
--- a/MFRC522.cpp
+++ b/MFRC522.cpp
@@ -322,39 +322,14 @@ bool MFRC522::PCD_PerformSelfTest() {
     // Determine firmware version (see section 9.3.4.8 in spec)
     byte version = PCD_ReadRegister(VersionReg);
 
-    // Reference values based on firmware version; taken from 16.1.1 in spec.
-    // Version 1.0
-    byte referenceV1_0[] = {
-        0x00, 0xC6, 0x37, 0xD5, 0x32, 0xB7, 0x57, 0x5C,
-        0xC2, 0xD8, 0x7C, 0x4D, 0xD9, 0x70, 0xC7, 0x73,
-        0x10, 0xE6, 0xD2, 0xAA, 0x5E, 0xA1, 0x3E, 0x5A,
-        0x14, 0xAF, 0x30, 0x61, 0xC9, 0x70, 0xDB, 0x2E,
-        0x64, 0x22, 0x72, 0xB5, 0xBD, 0x65, 0xF4, 0xEC,
-        0x22, 0xBC, 0xD3, 0x72, 0x35, 0xCD, 0xAA, 0x41,
-        0x1F, 0xA7, 0xF3, 0x53, 0x14, 0xDE, 0x7E, 0x02,
-        0xD9, 0x0F, 0xB5, 0x5E, 0x25, 0x1D, 0x29, 0x79
-    };
-
-    // Version 2.0
-    byte referenceV2_0[] = {
-        0x00, 0xEB, 0x66, 0xBA, 0x57, 0xBF, 0x23, 0x95,
-        0xD0, 0xE3, 0x0D, 0x3D, 0x27, 0x89, 0x5C, 0xDE,
-        0x9D, 0x3B, 0xA7, 0x00, 0x21, 0x5B, 0x89, 0x82,
-        0x51, 0x3A, 0xEB, 0x02, 0x0C, 0xA5, 0x00, 0x49,
-        0x7C, 0x84, 0x4D, 0xB3, 0xCC, 0xD2, 0x1B, 0x81,
-        0x5D, 0x48, 0x76, 0xD5, 0x71, 0x61, 0x21, 0xA9,
-        0x86, 0x96, 0x83, 0x38, 0xCF, 0x9D, 0x5B, 0x6D,
-        0xDC, 0x15, 0xBA, 0x3E, 0x7D, 0x95, 0x3B, 0x2F
-    };
-
     // Pick the appropriate reference values
-    byte *reference;
+    const byte *reference;
     switch (version) {
         case 0x91: // Version 1.0
-            reference = referenceV1_0;
+            reference = MFRC522_firmware_referenceV1_0;
             break;
         case 0x92: // Version 2.0
-            reference = referenceV2_0;
+            reference = MFRC522_firmware_referenceV2_0;
             break;
         default:   // Unknown version
             return false;
@@ -362,7 +337,7 @@ bool MFRC522::PCD_PerformSelfTest() {
 
     // Verify that the results match up to our expectations
     for (i = 0; i < 64; i++) {
-        if (result[i] != reference[i]) {
+        if (result[i] != pgm_read_byte(&(reference[i]))) {
             return false;
         }
     }
diff --git a/MFRC522.h b/MFRC522.h
index 1b6a9bc..b0429dd 100644
--- a/MFRC522.h
+++ b/MFRC522.h
@@ -78,6 +78,31 @@
 #include <Arduino.h>
 #include <SPI.h>
 
+// Firmware data for self-test
+// Reference values based on firmware version; taken from 16.1.1 in spec.
+// Version 1.0
+const byte MFRC522_firmware_referenceV1_0[] PROGMEM = {
+	0x00, 0xC6, 0x37, 0xD5, 0x32, 0xB7, 0x57, 0x5C,
+	0xC2, 0xD8, 0x7C, 0x4D, 0xD9, 0x70, 0xC7, 0x73,
+	0x10, 0xE6, 0xD2, 0xAA, 0x5E, 0xA1, 0x3E, 0x5A,
+	0x14, 0xAF, 0x30, 0x61, 0xC9, 0x70, 0xDB, 0x2E,
+	0x64, 0x22, 0x72, 0xB5, 0xBD, 0x65, 0xF4, 0xEC,
+	0x22, 0xBC, 0xD3, 0x72, 0x35, 0xCD, 0xAA, 0x41,
+	0x1F, 0xA7, 0xF3, 0x53, 0x14, 0xDE, 0x7E, 0x02,
+	0xD9, 0x0F, 0xB5, 0x5E, 0x25, 0x1D, 0x29, 0x79
+};
+// Version 2.0
+const byte MFRC522_firmware_referenceV2_0[] PROGMEM = {
+	0x00, 0xEB, 0x66, 0xBA, 0x57, 0xBF, 0x23, 0x95,
+	0xD0, 0xE3, 0x0D, 0x3D, 0x27, 0x89, 0x5C, 0xDE,
+	0x9D, 0x3B, 0xA7, 0x00, 0x21, 0x5B, 0x89, 0x82,
+	0x51, 0x3A, 0xEB, 0x02, 0x0C, 0xA5, 0x00, 0x49,
+	0x7C, 0x84, 0x4D, 0xB3, 0xCC, 0xD2, 0x1B, 0x81,
+	0x5D, 0x48, 0x76, 0xD5, 0x71, 0x61, 0x21, 0xA9,
+	0x86, 0x96, 0x83, 0x38, 0xCF, 0x9D, 0x5B, 0x6D,
+	0xDC, 0x15, 0xBA, 0x3E, 0x7D, 0x95, 0x3B, 0x2F
+};
+
 class MFRC522 {
 public:
 	// MFRC522 registers. Described in chapter 9 of the datasheet.