diff --git a/source/fatfs/diskio.c b/source/fatfs/diskio.c
index 3a73ce5..ad483fe 100644
--- a/source/fatfs/diskio.c
+++ b/source/fatfs/diskio.c
@@ -52,9 +52,9 @@ FATpartition DriveInfo[11] = {
 };
 
 SubtypeDesc SubTypes[5] = {
-    { 0x05CAE5, 0x179F1B, 0x4 },        // O3DS CTRNAND
-    { 0x05CAD7, 0x20E969, 0x5 },        // N3DS CTRNAND
-    { 0x05CAD7, 0x20E969, 0x4 },        // N3DS CTRNAND (downgraded)
+    { 0x05C980, 0x17AE80, 0x4 },        // O3DS CTRNAND
+    { 0x05C980, 0x20F680, 0x5 },        // N3DS CTRNAND
+    { 0x05C980, 0x20F680, 0x4 },        // N3DS CTRNAND (downgraded)
     { 0x000097, 0x047DA9, 0x3 },        // TWLN
     { 0x04808D, 0x0105B3, 0x3 }         // TWLP
 };
diff --git a/source/nand/nand.c b/source/nand/nand.c
index dfa756f..4dd3341 100644
--- a/source/nand/nand.c
+++ b/source/nand/nand.c
@@ -336,7 +336,11 @@ u32 CheckNandType(u32 nand_src)
     if (memcmp(NAND_BUFFER + 0x100, nand_magic_n3ds, 0x60) == 0) {
         return (GetUnitPlatform() == PLATFORM_3DS) ? 0 : NAND_TYPE_N3DS;
     } else if (memcmp(NAND_BUFFER + 0x100, nand_magic_o3ds, 0x60) == 0) {
-        return (GetUnitPlatform() == PLATFORM_3DS) ? NAND_TYPE_O3DS : NAND_TYPE_NO3DS;
+        u8 magic[8] = {0xE9, 0x00, 0x00, 0x43, 0x54, 0x52, 0x20, 0x20};
+        if (ReadNandSectors(NAND_BUFFER, 0x5CAE5, 1, 0x04, nand_src) != 0)
+            return 0;
+        return ((GetUnitPlatform() == PLATFORM_3DS) || (memcmp(magic, NAND_BUFFER, 8) == 0)) ?
+            NAND_TYPE_O3DS : NAND_TYPE_NO3DS;
     }
     
     return 0;