diff --git a/libfreefare/freefare.c b/libfreefare/freefare.c
index 4d4d5a9..f67608f 100644
--- a/libfreefare/freefare.c
+++ b/libfreefare/freefare.c
@@ -28,15 +28,12 @@
 
 #define NXP_MANUFACTURER_CODE 0x04
 
-/* Number of bytes of ATS to compare */
-#define ATS_LENGTH 4
-
 struct supported_tag supported_tags[] = {
-    { CLASSIC_1K, "Mifare Classic 1k",            0x08, 0, { 0x00 } },
-    { CLASSIC_4K, "Mifare Classic 4k",            0x18, 0, { 0x00 } },
-    { CLASSIC_4K, "Mifare Classic 4k (Emulated)", 0x38, 0, { 0x00 } },
-    { DESFIRE,    "Mifare DESFire",               0x20, 5, { 0x75, 0x77, 0x81, 0x02 /*, 0xXX */ }},
-    { ULTRALIGHT, "Mifare UltraLight",            0x00, 0, { 0x00 } },
+    { CLASSIC_1K, "Mifare Classic 1k",            0x08, 0, 0, { 0x00 } },
+    { CLASSIC_4K, "Mifare Classic 4k",            0x18, 0, 0, { 0x00 } },
+    { CLASSIC_4K, "Mifare Classic 4k (Emulated)", 0x38, 0, 0, { 0x00 } },
+    { DESFIRE,    "Mifare DESFire",               0x20, 5, 4, { 0x75, 0x77, 0x81, 0x02 /*, 0xXX */ }},
+    { ULTRALIGHT, "Mifare UltraLight",            0x00, 0, 0, { 0x00 } },
 };
 
 /*
@@ -53,8 +50,8 @@ freefare_tag_new (nfc_device_t *device, nfc_iso14443a_info_t nai)
     for (size_t i = 0; i < sizeof (supported_tags) / sizeof (struct supported_tag); i++) {
 	if (((nai.szUidLen == 4) || (nai.abtUid[0] == NXP_MANUFACTURER_CODE)) &&
 	    (nai.btSak == supported_tags[i].SAK) &&
-	    (!supported_tags[i].ATS_length || ((nai.szAtsLen == supported_tags[i].ATS_length) &&
-					       (0 == memcmp (nai.abtAts, supported_tags[i].ATS, ATS_LENGTH))))) {
+	    (!supported_tags[i].ATS_min_length || ((nai.szAtsLen >= supported_tags[i].ATS_min_length) &&
+					       (0 == memcmp (nai.abtAts, supported_tags[i].ATS, supported_tags[i].ATS_compare_length))))) {
 
 	    tag_info = &(supported_tags[i]);
 	    found = true;
diff --git a/libfreefare/freefare_internal.h b/libfreefare/freefare_internal.h
index 78268ea..59ce045 100644
--- a/libfreefare/freefare_internal.h
+++ b/libfreefare/freefare_internal.h
@@ -165,7 +165,8 @@ struct supported_tag {
     enum mifare_tag_type type;
     const char *friendly_name;
     uint8_t SAK;
-    uint8_t ATS_length;
+    uint8_t ATS_min_length;
+    uint8_t ATS_compare_length;
     uint8_t ATS[5];
 };