diff --git a/asm/rom_11B9C.s b/asm/rom_11B9C.s
index 453f097..dff80e5 100644
--- a/asm/rom_11B9C.s
+++ b/asm/rom_11B9C.s
@@ -51516,98 +51516,3 @@ _08031B20: .4byte 0x00000359
 _08031B24: .4byte gOamBuffer
 _08031B28: .4byte 0xFFFFFE00
 _08031B2C: .4byte 0x000001FF
-
-	thumb_func_start sub_31B30
-sub_31B30: @ 0x08031B30
-	push {r4, r5, r6, r7, lr}
-	ldr r1, _08031B64 @ =gMain
-	ldrb r0, [r1, #4]
-	ldr r2, _08031B68 @ =0x00004010
-	adds r6, r1, r2
-	cmp r0, #0
-	bne _08031B42
-	ldr r0, _08031B6C @ =0x00003D30
-	adds r6, r1, r0
-_08031B42:
-	ldrh r0, [r6]
-	cmp r0, #0
-	beq _08031BD6
-	ldr r0, _08031B70 @ =gCurrentPinballGame
-	ldr r1, [r0]
-	adds r0, r1, #0
-	adds r0, #0x4c
-	movs r2, #0
-	ldrsh r0, [r0, r2]
-	cmp r0, #7
-	bgt _08031B74
-	adds r0, r1, #0
-	adds r0, #0x58
-	ldrh r1, [r0]
-	movs r2, #8
-	rsbs r2, r2, #0
-	b _08031B7E
-	.align 2, 0
-_08031B64: .4byte gMain
-_08031B68: .4byte 0x00004010
-_08031B6C: .4byte 0x00003D30
-_08031B70: .4byte gCurrentPinballGame
-_08031B74:
-	adds r0, r1, #0
-	adds r0, #0x58
-	ldrh r1, [r0]
-	movs r2, #0x80
-	lsls r2, r2, #1
-_08031B7E:
-	adds r0, r2, #0
-	subs r0, r0, r1
-	strh r0, [r6, #2]
-	movs r0, #0
-	strh r0, [r6, #4]
-	ldr r7, _08031BDC @ =gOamBuffer
-	ldr r1, _08031BE0 @ =0xFFFFFE00
-	mov ip, r1
-_08031B8E:
-	lsls r5, r0, #0x10
-	asrs r5, r5, #0x10
-	lsls r3, r5, #3
-	adds r3, #8
-	adds r3, r6, r3
-	ldrh r4, [r3]
-	lsls r4, r4, #3
-	adds r4, r4, r7
-	movs r2, #2
-	ldrsh r1, [r3, r2]
-	movs r2, #2
-	ldrsh r0, [r6, r2]
-	adds r1, r1, r0
-	ldr r2, _08031BE4 @ =0x000001FF
-	adds r0, r2, #0
-	ands r1, r0
-	ldrh r2, [r4, #2]
-	mov r0, ip
-	ands r0, r2
-	orrs r0, r1
-	strh r0, [r4, #2]
-	ldrh r2, [r3]
-	lsls r2, r2, #3
-	adds r2, r2, r7
-	ldrb r0, [r6, #4]
-	ldrb r3, [r3, #4]
-	adds r0, r0, r3
-	lsls r1, r5, #5
-	adds r0, r0, r1
-	strb r0, [r2]
-	adds r5, #1
-	lsls r5, r5, #0x10
-	lsrs r0, r5, #0x10
-	asrs r5, r5, #0x10
-	cmp r5, #4
-	ble _08031B8E
-_08031BD6:
-	pop {r4, r5, r6, r7}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_08031BDC: .4byte gOamBuffer
-_08031BE0: .4byte 0xFFFFFE00
-_08031BE4: .4byte 0x000001FF
diff --git a/expected_objs/sub_31B30.o b/expected_objs/sub_31B30.o
deleted file mode 100644
index 4fa9b19..0000000
Binary files a/expected_objs/sub_31B30.o and /dev/null differ
diff --git a/include/functions.h b/include/functions.h
index d71519e..f061a22 100644
--- a/include/functions.h
+++ b/include/functions.h
@@ -554,7 +554,7 @@ extern void sub_30EB4();
 extern void sub_31144();
 extern void sub_313A0();
 extern void sub_31498();
-extern void sub_31B30();
+extern void sub_31B30(void);
 extern void sub_31BE8(s16);
 //extern ? sub_31CF8();
 //extern ? BuildSpeciesWeightsForCatchEmMode();
diff --git a/src/rom_31BE8.c b/src/rom_31BE8.c
index fd31d93..d53d80c 100644
--- a/src/rom_31BE8.c
+++ b/src/rom_31BE8.c
@@ -3,6 +3,39 @@
 #include "gba/gba.h"
 #include "constants/fields.h"
 
+void sub_31B30(void)
+{
+    s16 i;
+    struct SpriteGroup *group;
+
+    if (gMain.selectedField == FIELD_RUBY)
+        group = &gMain.spriteGroups[81];
+    else
+        group = &gMain.spriteGroups[85];
+
+    if (group->available)
+    {
+        if (gCurrentPinballGame->unk4C < 8)
+        {
+            group->baseX = gCurrentPinballGame->unk58;
+            group->baseX = -8 - group->baseX;
+        }
+        else
+        {
+            group->baseX = gCurrentPinballGame->unk58;
+            group->baseX = 256 - group->baseX;
+        }
+
+        group->baseY = 0;
+        for (i = 0; i < 5; i++)
+        {
+            struct OamDataSimple *oamSimple = &group->oam[i];
+            gOamBuffer[oamSimple->oamId].x = oamSimple->xOffset + group->baseX;
+            gOamBuffer[oamSimple->oamId].y = oamSimple->yOffset + group->baseY + i * 0x20;
+        }
+    }
+}
+
 /**
  * Executed when saving or loading from a main field
  * arg0