diff --git a/include/arm9/arm7_stub.h b/include/arm9/arm7_stub.h
index 5628660..91b5e22 100644
--- a/include/arm9/arm7_stub.h
+++ b/include/arm9/arm7_stub.h
@@ -5,4 +5,5 @@
 
 
 extern const u32 _arm7_stub_start[];
+extern const u32 _arm7_stub_swi[];
 extern const u32 _arm7_stub_end[];
diff --git a/include/arm9/hardware/lgy.h b/include/arm9/hardware/lgy.h
index f7c9c7c..749fb6a 100644
--- a/include/arm9/hardware/lgy.h
+++ b/include/arm9/hardware/lgy.h
@@ -2,5 +2,5 @@
 
 
 
-void LGY_prepareLegacyMode(void);
+void LGY_prepareLegacyMode(bool gbaBios);
 void LGY_backupGbaSave(void);
diff --git a/include/ipc_handler.h b/include/ipc_handler.h
index 8d6ca0e..c4c4c96 100644
--- a/include/ipc_handler.h
+++ b/include/ipc_handler.h
@@ -33,7 +33,7 @@
 
 typedef enum
 {
-	IPC_CMD9_PREPARE_AGB       = MAKE_CMD(0, 0, 0, 0),
+	IPC_CMD9_PREPARE_AGB       = MAKE_CMD(0, 0, 0, 1),
 	IPC_CMD9_PREPARE_POWER     = MAKE_CMD(1, 0, 0, 0)
 } IpcCmd9;
 
diff --git a/source/arm11/hardware/lgy.c b/source/arm11/hardware/lgy.c
index 9c7ecd6..8aadfa5 100644
--- a/source/arm11/hardware/lgy.c
+++ b/source/arm11/hardware/lgy.c
@@ -34,7 +34,8 @@ static void lgySleepIrqHandler(u32 intSource)
 
 void LGY_prepareLegacyMode(void)
 {
-	PXI_sendCmd(IPC_CMD9_PREPARE_AGB, NULL, 0);
+	const u32 cmdBuf = false;
+	PXI_sendCmd(IPC_CMD9_PREPARE_AGB, &cmdBuf, 1);
 
 	LGYFB_init();
 
diff --git a/source/arm9/arm7_stub.s b/source/arm9/arm7_stub.s
index 5471e1b..4645e3d 100644
--- a/source/arm9/arm7_stub.s
+++ b/source/arm9/arm7_stub.s
@@ -3,56 +3,51 @@
 .fpu softvfp
 
 .global _arm7_stub_start
+.global _arm7_stub_swi
 .global _arm7_stub_end
 
 .type _arm7_stub_start %function
-.type gbaReset %function
-.type waitCycles %function
 
 
 .align 2
+@ Must be located at 0x3007E00.
 _arm7_stub_start:
 	mov r0, #0xD3
+	adr r1, _arm7_stub_start + 0x200  @ 0x3008000
 	msr CPSR_cxsf, r0
-	ldr sp, =0x03008000
 	mov r0, #0xD2
+	mov sp, r1
 	msr CPSR_cxsf, r0
-	ldr sp, =0x03007FA0
 	mov r0, #0xDF
+	sub sp, r1, #0x60  @ 0x3007FA0
 	msr CPSR_cxsf, r0
-	ldr sp, =0x03007F80
-	mov r3, #0x04700000
-	mov r0, #1
-	str r0, [r3]        @ Disable BIOS overlay.
-	mov r0, #0x100
-	bl  waitCycles
-	ldr r0, =0x1999E8
-	bl  waitCycles
+	mov r3, #0x4700000
+	adr r2, _arm7_stub_16 + 1
+	sub sp, r1, #0x80  @ 0x3007F80
+	bx  r2
 
-	ldr r3, =0x04000006 @ REG_VCOUNT
+.thumb
+_arm7_stub_16:
+	mov r0, #1
+	str r0, [r3]  @ Disable BIOS overlay.
+	@ The original ARM7 stub waits 256 cycles here (for the BIOS overlay disable?).
+	@ The original ARM7 stub waits 1677800 cycles (100 ms) here.
+
+	lsl  r3, r0, #26   @ 0x4000000
 wait_vcount_160_lp:
-	ldrb r0, [r3]
-	cmp  r0, #160       @ Wait for REG_VCOUNT = 160.
+	ldrb r0, [r3, #6]  @ REG_VCOUNT
+	cmp  r0, #160      @ Wait for REG_VCOUNT == 160.
 	bne  wait_vcount_160_lp
 
+	mov  r4, r3     @ Needed for function call 0xBC below.
 	mov  r0, #0xFF
-	bl   gbaReset
+_arm7_stub_swi:
+	swi  0x10       @ RegisterRamReset
+	@swi  0x26       @ HardReset (BIOS animation)
+	mov  r0, #0xBC
 	mov  r2, #0
-	mov  r4, #0x04000000
-	mov  lr, #0xBC
-	bx   lr
+	bx   r0
 .pool
 
-
-gbaReset:
-	swi 0x10000   @ RegisterRamReset
-	@swi 0x260000  @ HardReset
-	bx lr
-
-
-waitCycles:
-	subs r0, r0, #4
-	bcs waitCycles
-	bx lr
-
+.align 2
 _arm7_stub_end:
diff --git a/source/arm9/hardware/lgy.c b/source/arm9/hardware/lgy.c
index 69ff7bc..d00bb2d 100644
--- a/source/arm9/hardware/lgy.c
+++ b/source/arm9/hardware/lgy.c
@@ -22,8 +22,12 @@
 #define REGs_LGY_GBA_SAVE_TIMING   ((vu32*)(LGY_REGS_BASE + 0x120))
 
 
-#define MAX_ROM_SIZE   (1024u * 1024u * 32u)
-#define MAX_SAVE_SIZE  (1024u * 128u)
+#define MAX_ROM_SIZE    (1024u * 1024u * 32u)
+#define MAX_SAVE_SIZE   (1024u * 128u)
+#define ARM7_STUB_LOC   (0x3007E00u)
+#define ARM7_STUB_LOC9  (0x80BFE00u)
+#define ROM_LOC         (0x20000000u)
+#define SAVE_LOC        (0x08080000u)
 
 
 static FATFS g_sd = {0};
@@ -32,16 +36,17 @@ static u32 g_saveHash[8] = {0};
 
 
 
-void LGY_prepareLegacyMode(void)
+void LGY_prepareLegacyMode(bool gbaBios)
 {
 	REG_LGY_MODE = 2; // GBA mode
 
 	// BIOS overlay
 	REGs_LGY_A7_VECTOR[0] = 0xE51FF004; //ldr pc, [pc, #-4]
-	REGs_LGY_A7_VECTOR[1] = 0x03007E00;
-	// GBA address: 0x03007E00
-	NDMA_copy((u32*)0x080BFE00, _arm7_stub_start, (u32)_arm7_stub_end - (u32)_arm7_stub_start);
-	//iomemcpy((u32*)0x080BFE00, _arm7_stub_start, (u32)_arm7_stub_end - (u32)_arm7_stub_start);
+	REGs_LGY_A7_VECTOR[1] = ARM7_STUB_LOC;
+	NDMA_copy((u32*)ARM7_STUB_LOC9, _arm7_stub_start, (u32)_arm7_stub_end - (u32)_arm7_stub_start);
+	//iomemcpy((u32*)ARM7_STUB_LOC9, _arm7_stub_start, (u32)_arm7_stub_end - (u32)_arm7_stub_start);
+	// Patch swi 0x10 (RegisterRamReset) to swi 0x26 (HardReset).
+	if(gbaBios) *((u8*)(ARM7_STUB_LOC9 + ((u32)_arm7_stub_swi - (u32)_arm7_stub_start))) = 0x26;
 
 	REG_LGY_GBA_SAVE_TYPE = 0xE;
 	static const u32 saveStuff[4] = {0x27C886, 0x8CE35, 0x184, 0x31170};
@@ -55,7 +60,7 @@ void LGY_prepareLegacyMode(void)
 		{
 			if((romSize = f_size(&f)) > MAX_ROM_SIZE) panic();
 
-			u8 *ptr = (u8*)0x20000000u;
+			u8 *ptr = (u8*)ROM_LOC;
 			UINT read;
 			FRESULT res;
 			while((res = f_read(&f, ptr, 0x100000u, &read)) == FR_OK && read == 0x100000u)
@@ -70,17 +75,17 @@ void LGY_prepareLegacyMode(void)
 		if(f_open(&f, "sdmc:/rom.sav", FA_OPEN_EXISTING | FA_READ) == FR_OK)
 		{
 			UINT read;
-			if(f_read(&f, (void*)0x08080000, MAX_SAVE_SIZE, &read) != FR_OK) panic();
+			if(f_read(&f, (void*)SAVE_LOC, MAX_SAVE_SIZE, &read) != FR_OK) panic();
 			f_close(&f);
 
-			sha((u32*)0x08080000, g_saveSize, g_saveHash, SHA_INPUT_BIG | SHA_MODE_256, SHA_OUTPUT_BIG);
+			sha((u32*)SAVE_LOC, g_saveSize, g_saveHash, SHA_INPUT_BIG | SHA_MODE_256, SHA_OUTPUT_BIG);
 		}
-		else NDMA_fill((u32*)0x08080000, 0xFFFFFFFFu, g_saveSize);
+		else NDMA_fill((u32*)SAVE_LOC, 0xFFFFFFFFu, g_saveSize);
 	}
 
 	// Pad ROM area with "open bus" value.
 	if(romSize < MAX_ROM_SIZE)
-		NDMA_fill((u32*)(0x20000000 + romSize), 0xFFFFFFFFu, MAX_ROM_SIZE - romSize);
+		NDMA_fill((u32*)(ROM_LOC + romSize), 0xFFFFFFFFu, MAX_ROM_SIZE - romSize);
 }
 
 void LGY_backupGbaSave(void)
@@ -91,14 +96,14 @@ void LGY_backupGbaSave(void)
 		REG_LGY_GBA_SAVE_MAP = 1;
 
 		u32 newHash[8];
-		sha((u32*)0x08080000, g_saveSize, newHash, SHA_INPUT_BIG | SHA_MODE_256, SHA_OUTPUT_BIG);
+		sha((u32*)SAVE_LOC, g_saveSize, newHash, SHA_INPUT_BIG | SHA_MODE_256, SHA_OUTPUT_BIG);
 		if(memcmp(g_saveHash, newHash, 32) != 0) // Backup save if it changed.
 		{
 			FIL f;
 			if(f_open(&f, "sdmc:/rom.sav", FA_OPEN_ALWAYS | FA_WRITE) == FR_OK)
 			{
 				UINT written;
-				if(f_write(&f, (void*)0x08080000, g_saveSize, &written) != FR_OK) panic();
+				if(f_write(&f, (void*)SAVE_LOC, g_saveSize, &written) != FR_OK) panic();
 				f_close(&f);
 			}
 		}
diff --git a/source/arm9/ipc_handler.c b/source/arm9/ipc_handler.c
index 8f92343..fc09303 100644
--- a/source/arm9/ipc_handler.c
+++ b/source/arm9/ipc_handler.c
@@ -36,7 +36,7 @@ u32 IPC_handleCmd(u8 cmdId, u32 inBufs, u32 outBufs, const u32 *const buf)
 	switch(cmdId)
 	{
 		case IPC_CMD_ID_MASK(IPC_CMD9_PREPARE_AGB):
-			LGY_prepareLegacyMode();
+			LGY_prepareLegacyMode(*buf);
 			break;
 		case IPC_CMD_ID_MASK(IPC_CMD9_PREPARE_POWER):
 			LGY_backupGbaSave();