diff --git a/asm/region_map.s b/asm/region_map.s
index 7cc1b8d925..f144c39a21 100644
--- a/asm/region_map.s
+++ b/asm/region_map.s
@@ -5,310 +5,6 @@
 
 	.text
 
-	thumb_func_start sub_8122D88
-sub_8122D88: @ 8122D88
-	push {r4,lr}
-	ldr r4, =gUnknown_0203A144
-	str r0, [r4]
-	bl sub_81238AC
-	ldr r2, [r4]
-	adds r0, r2, 0
-	adds r0, 0x54
-	ldrh r1, [r0]
-	adds r0, 0x20
-	strh r1, [r0]
-	subs r0, 0x1E
-	ldrh r1, [r0]
-	adds r0, 0x20
-	strh r1, [r0]
-	pop {r4}
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end sub_8122D88
-
-	thumb_func_start sub_8122DB0
-sub_8122DB0: @ 8122DB0
-	push {r4,r5,lr}
-	sub sp, 0xC
-	ldr r0, =gUnknown_0203A144
-	ldr r0, [r0]
-	adds r0, 0x79
-	ldrb r0, [r0]
-	cmp r0, 0x7
-	bls _08122DC2
-	b _0812300C
-_08122DC2:
-	lsls r0, 2
-	ldr r1, =_08122DD4
-	adds r0, r1
-	ldr r0, [r0]
-	mov pc, r0
-	.pool
-	.align 2, 0
-_08122DD4:
-	.4byte _08122DF4
-	.4byte _08122E2C
-	.4byte _08122E78
-	.4byte _08122E94
-	.4byte _08122EB0
-	.4byte _08122ECC
-	.4byte _08122F10
-	.4byte _08122F8C
-_08122DF4:
-	ldr r0, =gUnknown_0203A144
-	ldr r1, [r0]
-	adds r0, r1, 0
-	adds r0, 0x83
-	ldrb r0, [r0]
-	cmp r0, 0
-	beq _08122E18
-	adds r0, r1, 0
-	adds r0, 0x80
-	ldrb r0, [r0]
-	ldr r1, =gUnknown_0859F77C
-	movs r2, 0
-	str r2, [sp]
-	b _08122E52
-	.pool
-_08122E18:
-	ldr r0, =gUnknown_0859F77C
-	ldr r1, =0x06008000
-	bl LZ77UnCompVram
-	b _08123014
-	.pool
-_08122E2C:
-	ldr r4, =gUnknown_0203A144
-	ldr r0, [r4]
-	adds r0, 0x83
-	ldrb r0, [r0]
-	cmp r0, 0
-	beq _08122E64
-	bl free_temp_tile_data_buffers_if_possible
-	lsls r0, 24
-	cmp r0, 0
-	beq _08122E44
-	b _08123014
-_08122E44:
-	ldr r0, [r4]
-	adds r0, 0x80
-	ldrb r0, [r0]
-	ldr r1, =gUnknown_085A04E0
-	movs r2, 0x1
-	str r2, [sp]
-	movs r2, 0
-_08122E52:
-	movs r3, 0
-	bl decompress_and_copy_tile_data_to_vram
-	b _08123014
-	.pool
-_08122E64:
-	ldr r0, =gUnknown_085A04E0
-	ldr r1, =0x0600e000
-	bl LZ77UnCompVram
-	b _08123014
-	.pool
-_08122E78:
-	bl free_temp_tile_data_buffers_if_possible
-	lsls r0, 24
-	cmp r0, 0
-	beq _08122E84
-	b _08123014
-_08122E84:
-	ldr r0, =gUnknown_0859F73C
-	movs r1, 0x70
-	movs r2, 0x60
-	bl LoadPalette
-	b _08123014
-	.pool
-_08122E94:
-	ldr r0, =gUnknown_0859F60C
-	ldr r1, =gUnknown_0203A144
-	ldr r1, [r1]
-	movs r2, 0xC2
-	lsls r2, 1
-	adds r1, r2
-	bl LZ77UnCompWram
-	b _08123014
-	.pool
-_08122EB0:
-	ldr r0, =gUnknown_0859F650
-	ldr r1, =gUnknown_0203A144
-	ldr r1, [r1]
-	movs r5, 0xA1
-	lsls r5, 2
-	adds r1, r5
-	bl LZ77UnCompWram
-	b _08123014
-	.pool
-_08122ECC:
-	bl sub_81238AC
-	ldr r4, =gUnknown_0203A144
-	ldr r2, [r4]
-	adds r0, r2, 0
-	adds r0, 0x54
-	ldrh r1, [r0]
-	adds r0, 0x20
-	strh r1, [r0]
-	subs r0, 0x1E
-	ldrh r0, [r0]
-	adds r1, r2, 0
-	adds r1, 0x76
-	strh r0, [r1]
-	ldrh r0, [r2]
-	bl sub_8123EB4
-	ldr r1, [r4]
-	strh r0, [r1]
-	ldrh r0, [r1]
-	bl get_flagnr_blue_points
-	ldr r1, [r4]
-	strb r0, [r1, 0x2]
-	ldr r1, [r4]
-	adds r0, r1, 0x4
-	ldrh r1, [r1]
-	movs r2, 0x10
-	bl GetMapName
-	b _08123014
-	.pool
-_08122F10:
-	ldr r0, =gUnknown_0203A144
-	ldr r4, [r0]
-	adds r0, r4, 0
-	adds r0, 0x78
-	ldrb r1, [r0]
-	cmp r1, 0
-	bne _08122F3C
-	movs r0, 0x80
-	lsls r0, 1
-	str r0, [sp]
-	str r0, [sp, 0x4]
-	str r1, [sp, 0x8]
-	movs r0, 0
-	movs r1, 0
-	movs r2, 0
-	movs r3, 0
-	bl sub_81236C4
-	b _08123014
-	.pool
-_08122F3C:
-	adds r1, r4, 0
-	adds r1, 0x54
-	ldrh r0, [r1]
-	lsls r0, 3
-	subs r0, 0x34
-	adds r2, r4, 0
-	adds r2, 0x5C
-	movs r3, 0
-	strh r0, [r2]
-	movs r0, 0x56
-	adds r0, r4
-	mov r12, r0
-	ldrh r0, [r0]
-	lsls r0, 3
-	subs r0, 0x44
-	adds r5, r4, 0
-	adds r5, 0x5E
-	strh r0, [r5]
-	ldrh r1, [r1]
-	adds r0, r4, 0
-	adds r0, 0x64
-	strh r1, [r0]
-	mov r0, r12
-	ldrh r1, [r0]
-	adds r0, r4, 0
-	adds r0, 0x66
-	strh r1, [r0]
-	movs r1, 0
-	ldrsh r0, [r2, r1]
-	movs r2, 0
-	ldrsh r1, [r5, r2]
-	movs r2, 0x80
-	str r2, [sp]
-	str r2, [sp, 0x4]
-	str r3, [sp, 0x8]
-	movs r2, 0x38
-	movs r3, 0x48
-	bl sub_81236C4
-	b _08123014
-_08122F8C:
-	bl sub_8123FB0
-	bl sub_81237B4
-	ldr r4, =gUnknown_0203A144
-	ldr r0, [r4]
-	movs r1, 0
-	str r1, [r0, 0x1C]
-	str r1, [r0, 0x20]
-	adds r0, 0x7A
-	strb r1, [r0]
-	ldr r0, [r4]
-	adds r0, 0x7E
-	strb r1, [r0]
-	ldr r1, [r4]
-	adds r0, r1, 0
-	adds r0, 0x83
-	ldrb r0, [r0]
-	cmp r0, 0
-	beq _08123002
-	adds r0, r1, 0
-	adds r0, 0x80
-	ldrb r0, [r0]
-	movs r1, 0x3
-	movs r2, 0x2
-	bl SetBgAttribute
-	ldr r1, [r4]
-	adds r0, r1, 0
-	adds r0, 0x80
-	ldrb r0, [r0]
-	adds r1, 0x81
-	ldrb r2, [r1]
-	movs r1, 0x1
-	bl SetBgAttribute
-	ldr r1, [r4]
-	adds r0, r1, 0
-	adds r0, 0x80
-	ldrb r0, [r0]
-	adds r1, 0x82
-	ldrb r2, [r1]
-	movs r1, 0x2
-	bl SetBgAttribute
-	ldr r0, [r4]
-	adds r0, 0x80
-	ldrb r0, [r0]
-	movs r1, 0x6
-	movs r2, 0x1
-	bl SetBgAttribute
-	ldr r0, [r4]
-	adds r0, 0x80
-	ldrb r0, [r0]
-	movs r1, 0x4
-	movs r2, 0x1
-	bl SetBgAttribute
-_08123002:
-	ldr r1, [r4]
-	adds r1, 0x79
-	ldrb r0, [r1]
-	adds r0, 0x1
-	strb r0, [r1]
-_0812300C:
-	movs r0, 0
-	b _08123022
-	.pool
-_08123014:
-	ldr r0, =gUnknown_0203A144
-	ldr r1, [r0]
-	adds r1, 0x79
-	ldrb r0, [r1]
-	adds r0, 0x1
-	strb r0, [r1]
-	movs r0, 0x1
-_08123022:
-	add sp, 0xC
-	pop {r4,r5}
-	pop {r1}
-	bx r1
-	.pool
-	thumb_func_end sub_8122DB0
-
 	thumb_func_start sub_8123030
 sub_8123030: @ 8123030
 	push {lr}
diff --git a/include/region_map.h b/include/region_map.h
index 478a4faaaa..316b6f3a11 100644
--- a/include/region_map.h
+++ b/include/region_map.h
@@ -226,28 +226,45 @@ struct UnkStruct_8122CF8 {
 };
 
 struct RegionMap {
-    /*0x000*/ u8 unk_00;
-    /*0x001*/ u8 unk_01;
-    /*0x002*/ bool8 unk_02;
-    /*0x003*/ u8 unk_03;
+    /*0x000*/ u16 mapSecId;
+    /*0x002*/ u8 unk_002;
+    /*0x003*/ u8 unk_003;
     /*0x004*/ u8 mapSecName[0x14];
     /*0x018*/ u8 (*inputCallback)(void);
-    /*0x01c*/ u8 filler_01c[0x5c];
+    /*0x01c*/ u32 unk_01c;
+    /*0x020*/ u32 unk_020;
+    /*0x024*/ u8 filler_024[0x30];
+    /*0x054*/ u16 unk_054;
+    /*0x056*/ u16 unk_056;
+    /*0x058*/ u8 filler_058[0x4];
+    /*0x05c*/ s16 unk_05c;
+    /*0x05e*/ s16 unk_05e;
+    /*0x060*/ u8 filler_060[0x4];
+    /*0x064*/ u16 unk_064;
+    /*0x066*/ u16 unk_066;
+    /*0x068*/ u8 filler_068[0xc];
+    /*0x074*/ u16 unk_074;
+    /*0x076*/ u16 unk_076;
     /*0x078*/ u8 unk_078;
-    /*0x079*/ bool8 unk_079;
-    /*0x07a*/ u8 filler_07a[6];
+    /*0x079*/ u8 unk_079;
+    /*0x07a*/ u8 unk_07a;
+    /*0x07b*/ u8 filler_07b[3];
+    /*0x07e*/ u8 unk_07e;
+    /*0x07f*/ u8 filler_07f[1];
     /*0x080*/ u8 unk_080;
     /*0x081*/ u8 unk_081;
     /*0x082*/ u8 unk_082;
     /*0x083*/ bool8 unk_083;
-    /*0x084*/ u8 filler_084[0x800];
+    /*0x084*/ u8 filler_084[0x100];
+    /*0x184*/ u8 unk_184[0x100];
+    /*0x284*/ u8 unk_284[0x600];
 }; // size = 0x884
 
 // Exported RAM declarations
 
 // Exported ROM declarations
 void GetMapName(u8 *, u16, u16);
-void sub_8122CDC(struct RegionMap *regionMap, bool8 argument);
+void sub_8122CDC(struct RegionMap *regionMap, u8 argument);
 void sub_8124288(u16 x, u16 y);
 void sub_81240D4(u16 x, u16 y);
 u8 sub_81230AC(void);
diff --git a/src/field_region_map.c b/src/field_region_map.c
index e8c52de77d..74b62bbc79 100644
--- a/src/field_region_map.c
+++ b/src/field_region_map.c
@@ -120,7 +120,7 @@ void sub_8170290(void)
     switch (gUnknown_0203BCD0->state)
     {
         case 0:
-            sub_8122CDC(&gUnknown_0203BCD0->regionMap, FALSE);
+            sub_8122CDC(&gUnknown_0203BCD0->regionMap, 0);
             sub_8124288(0, 0);
             sub_81240D4(1, 1);
             gUnknown_0203BCD0->state ++;
@@ -181,7 +181,7 @@ void sub_8170290(void)
 
 static void sub_8170428(void)
 {
-    if (gUnknown_0203BCD0->regionMap.unk_02)
+    if (gUnknown_0203BCD0->regionMap.unk_002 != 0)
     {
         FillWindowPixelBuffer(0, 0x11);
         PrintTextOnWindow(0, 1, gUnknown_0203BCD0->regionMap.mapSecName, 0, 1, 0, NULL);
diff --git a/src/region_map.c b/src/region_map.c
index 1f54108d6b..dc53f1ec6b 100644
--- a/src/region_map.c
+++ b/src/region_map.c
@@ -2,6 +2,9 @@
 // Includes
 #include "global.h"
 #include "region_map.h"
+#include "menu.h"
+#include "palette.h"
+#include "bg.h"
 
 // Static type declarations
 
@@ -20,18 +23,30 @@ void sub_8122CF8(struct RegionMap *regionMap, struct UnkStruct_8122CF8 *arg1, bo
 bool8 sub_8122DB0(void);
 u8 sub_8123254(void);
 u8 sub_81230C4(void);
+void sub_81238AC(void);
+u16 sub_8123EB4(u16 mapSecId);
+u8 get_flagnr_blue_points(u16 mapSecId);
+void sub_81236C4(s32 a0, s32 a1, s32 a2, s32 a3, u16 a4, u16 a5, u16 a6);
+void sub_8123FB0(void);
+void sub_81237B4(void);
 
 // .rodata
 
+extern const u8 gUnknown_0859F77C[];
+extern const u8 gUnknown_085A04E0[];
+extern const u16 gUnknown_0859F73C[];
+extern const u8 gUnknown_0859F60C[];
+extern const u8 gUnknown_0859F650[];
+
 // .text
 
-void sub_8122CDC(struct RegionMap *regionMap, bool8 argument)
+void sub_8122CDC(struct RegionMap *regionMap, u8 argument)
 {
     sub_8122CF8(regionMap, NULL, argument);
     while (sub_8122DB0());
 }
 
-void sub_8122CF8(struct RegionMap *regionMap, struct UnkStruct_8122CF8 *arg1, bool8 arg2)
+void sub_8122CF8(struct RegionMap *regionMap, struct UnkStruct_8122CF8 *arg1, u8 arg2)
 {
     gUnknown_0203A144 = regionMap;
     gUnknown_0203A144->unk_079 = 0;
@@ -52,3 +67,96 @@ void sub_8122CF8(struct RegionMap *regionMap, struct UnkStruct_8122CF8 *arg1, bo
         gUnknown_0203A144->unk_083 = FALSE;
     }
 }
+
+void sub_8122D88(struct RegionMap *regionMap)
+{
+    gUnknown_0203A144 = regionMap;
+    sub_81238AC();
+    gUnknown_0203A144->unk_074 = gUnknown_0203A144->unk_054;
+    gUnknown_0203A144->unk_076 = gUnknown_0203A144->unk_056;
+}
+
+bool8 sub_8122DB0(void)
+{
+    switch (gUnknown_0203A144->unk_079)
+    {
+        case 0:
+            if (gUnknown_0203A144->unk_083)
+            {
+                decompress_and_copy_tile_data_to_vram(gUnknown_0203A144->unk_080, gUnknown_0859F77C, 0, 0, 0);
+            }
+            else
+            {
+                LZ77UnCompVram(gUnknown_0859F77C, (u16 *)BG_SCREEN_ADDR(16));
+            }
+            break;
+        case 1:
+            if (gUnknown_0203A144->unk_083)
+            {
+                if (!free_temp_tile_data_buffers_if_possible())
+                {
+                    decompress_and_copy_tile_data_to_vram(gUnknown_0203A144->unk_080, gUnknown_085A04E0, 0, 0, 1);
+                }
+            }
+            else
+            {
+                LZ77UnCompVram(gUnknown_085A04E0, (u16 *)BG_SCREEN_ADDR(28));
+            }
+            break;
+        case 2:
+            if (!free_temp_tile_data_buffers_if_possible())
+            {
+                LoadPalette(gUnknown_0859F73C, 0x70, 0x60);
+            }
+            break;
+        case 3:
+            LZ77UnCompWram(gUnknown_0859F60C, gUnknown_0203A144->unk_184);
+            break;
+        case 4:
+            LZ77UnCompWram(gUnknown_0859F650, gUnknown_0203A144->unk_284);
+            break;
+        case 5:
+            sub_81238AC();
+            gUnknown_0203A144->unk_074 = gUnknown_0203A144->unk_054;
+            gUnknown_0203A144->unk_076 = gUnknown_0203A144->unk_056;
+            gUnknown_0203A144->mapSecId = sub_8123EB4(gUnknown_0203A144->mapSecId);
+            gUnknown_0203A144->unk_002 = get_flagnr_blue_points(gUnknown_0203A144->mapSecId);
+            GetMapName(gUnknown_0203A144->mapSecName, gUnknown_0203A144->mapSecId, 16);
+            break;
+        case 6:
+            if (gUnknown_0203A144->unk_078 == 0)
+            {
+                sub_81236C4(0, 0, 0, 0, 0x100, 0x100, 0);
+            }
+            else
+            {
+                gUnknown_0203A144->unk_05c = gUnknown_0203A144->unk_054 * 8 - 0x34;
+                gUnknown_0203A144->unk_05e = gUnknown_0203A144->unk_056 * 8 - 0x44;
+                gUnknown_0203A144->unk_064 = gUnknown_0203A144->unk_054;
+                gUnknown_0203A144->unk_066 = gUnknown_0203A144->unk_056;
+                sub_81236C4(gUnknown_0203A144->unk_05c, gUnknown_0203A144->unk_05e, 0x38, 0x48, 0x80, 0x80, 0);
+            }
+            break;
+        case 7:
+            sub_8123FB0();
+            sub_81237B4();
+            gUnknown_0203A144->unk_01c = 0;
+            gUnknown_0203A144->unk_020 = 0;
+            gUnknown_0203A144->unk_07a = 0;
+            gUnknown_0203A144->unk_07e = 0;
+            if (gUnknown_0203A144->unk_083)
+            {
+                SetBgAttribute(gUnknown_0203A144->unk_080, BG_CTRL_ATTR_MAPBASEINDEX, 2);
+                SetBgAttribute(gUnknown_0203A144->unk_080, BG_CTRL_ATTR_VISIBLE, gUnknown_0203A144->unk_081);
+                SetBgAttribute(gUnknown_0203A144->unk_080, BG_CTRL_ATTR_CHARBASEINDEX, gUnknown_0203A144->unk_082);
+                SetBgAttribute(gUnknown_0203A144->unk_080, BG_CTRL_ATTR_PRIORITY, 1);
+                SetBgAttribute(gUnknown_0203A144->unk_080, BG_CTRL_ATTR_SCREENSIZE, 1);
+            }
+            gUnknown_0203A144->unk_079 ++;
+            return FALSE;
+        default:
+            return FALSE;
+    }
+    gUnknown_0203A144->unk_079 ++;
+    return TRUE;
+}