Support additional EmuNAND layouts.

Fixes compatibility with a second EmuNAND placed after an EmuNAND
created with either the 'default' or 'minimum' setup sizes with EmuNAND9
/ 3DS Multi EmuNAND Creator.

source/emunand.c

@@ -25,37 +25,59 @@
 #include "fatfs/sdmmc/sdmmc.h"
 #include "../build/emunandpatch.h"
 
+#define O3DS_LEGACY_FAT		0x200000
+#define O3DS_DEFAULT_FAT	0x1DE000
+#define O3DS_MINIMUM_FAT	0x1D8000
+
+#define N3DS_LEGACY_FAT		0x400000
+#define N3DS_DEFAULT_FAT	0x3B2000
+#define N3DS_MINIMUM_FAT	0x26E000
+
 void locateEmuNand(u32 *off, u32 *head, FirmwareSource *emuNand)
 {
     static u8 temp[0x200];
-
+	
     const u32 nandSize = getMMCDevice(0)->total_size;
-    u32 nandOffset = *emuNand == FIRMWARE_EMUNAND ? 0 :
+	const u32 nandLayoutO3DS[3] = { O3DS_LEGACY_FAT, O3DS_DEFAULT_FAT, O3DS_MINIMUM_FAT }; // Legacy, Default, Minimum
-                                  (nandSize > 0x200000 ? 0x400000 : 0x200000);
+	const u32 nandLayoutN3DS[3] = { N3DS_LEGACY_FAT, N3DS_DEFAULT_FAT, N3DS_MINIMUM_FAT }; // Legacy, Default, Minimum
-
+	
-    //Check for RedNAND
+	u8 i;
-    if(!sdmmc_sdcard_readsectors(nandOffset + 1, 1, temp) &&
+	u32 nandOffset;
-       *(u32 *)(temp + 0x100) == NCSD_MAGIC)
+	bool found = false;
-    {
+	
-        *off = nandOffset + 1;
+	for (i = 0; i < 3; i++)
-        *head = nandOffset + 1;
+	{
-    }
+		 if (i > 0 && *emuNand != FIRMWARE_EMUNAND2) break;
-
+		
-    //Check for Gateway emuNAND
+		// Check for 'Legacy', 'Default' and 'Minimum' partition layouts when checking for the 2nd EmuNAND
-    else if(!sdmmc_sdcard_readsectors(nandOffset + nandSize, 1, temp) &&
+		nandOffset = (*emuNand == FIRMWARE_EMUNAND ? 0 : (isN3DS ? nandLayoutN3DS[i] : nandLayoutO3DS[i]));
-            *(u32 *)(temp + 0x100) == NCSD_MAGIC)
+		
-    {
+		//Check for RedNAND
-        *off = nandOffset;
+		if(!sdmmc_sdcard_readsectors(nandOffset + 1, 1, temp) && *(u32 *)(temp + 0x100) == NCSD_MAGIC)
-        *head = nandOffset + nandSize;
+		{
-    }
+			*off = nandOffset + 1;
-
+			*head = nandOffset + 1;
+			found = true;
+			break;
+		}
+		
+		//Check for Gateway emuNAND
+		else if(!sdmmc_sdcard_readsectors(nandOffset + nandSize, 1, temp) && *(u32 *)(temp + 0x100) == NCSD_MAGIC)
+		{
+			*off = nandOffset;
+			*head = nandOffset + nandSize;
+			found = true;
+			break;
+		}
+	}
+	
     /* Fallback to the first emuNAND if there's no second one,
        or to SysNAND if there isn't any */
-    else
+	if (!found)
-    {
+	{
         *emuNand = (*emuNand == FIRMWARE_EMUNAND2) ? FIRMWARE_EMUNAND : FIRMWARE_SYSNAND;
         if(*emuNand) locateEmuNand(off, head, emuNand);
-    }
+	}
 }
 
 static inline u8 *getFreeK9Space(u8 *pos, u32 size)

source/emunand.h

@@ -27,6 +27,7 @@
 #define NCSD_MAGIC 0x4453434E
 
 extern u32 emuOffset;
+extern bool isN3DS;
 
 void locateEmuNand(u32 *off, u32 *head, FirmwareSource *emuNand);
 void patchEmuNand(u8 *arm9Section, u32 arm9SectionSize, u8 *process9Offset, u32 process9Size, u32 emuHeader, u32 branchAdditive);