diff --git a/asm/include/overlay_11_022EBC18.inc b/asm/include/overlay_11_022EBEAC.inc
similarity index 99%
rename from asm/include/overlay_11_022EBC18.inc
rename to asm/include/overlay_11_022EBEAC.inc
index 5d43b8e4..c82bdca7 100644
--- a/asm/include/overlay_11_022EBC18.inc
+++ b/asm/include/overlay_11_022EBEAC.inc
@@ -323,6 +323,7 @@
 .public ov11_022EB2F4
 .public ov11_022EB3C8
 .public ov11_022EBAA0
+.public ov11_022EBC18
 .public ov11_02316AFC
 .public ov11_02316B04
 .public ov11_02316B14
@@ -2322,7 +2323,6 @@
 .public sub_0200B33C
 .public sub_0200B340
 .public sub_0200B3C0
-.public sub_0200B500
 .public sub_0200CF6C
 .public sub_0200D310
 .public sub_0200D65C
diff --git a/asm/overlay_11_022EBC18.s b/asm/overlay_11_022EBEAC.s
similarity index 99%
rename from asm/overlay_11_022EBC18.s
rename to asm/overlay_11_022EBEAC.s
index 93450a50..3c4b640f 100644
--- a/asm/overlay_11_022EBC18.s
+++ b/asm/overlay_11_022EBEAC.s
@@ -1,194 +1,8 @@
 	.include "asm/macros.inc"
-	.include "overlay_11_022EBC18.inc"
+	.include "overlay_11_022EBEAC.inc"
 
 	.text
 
-	arm_func_start ov11_022EBC18
-ov11_022EBC18: ; 0x022EBC18
-	stmdb sp!, {r3, r4, r5, r6, r7, r8, sb, sl, fp, lr}
-	sub sp, sp, #8
-	mov sl, r0
-	mov r5, r1
-	add r4, sl, #0x2bc
-	ldmia r5!, {r0, r1, r2, r3}
-	stmia r4!, {r0, r1, r2, r3}
-	ldmia r5, {r0, r1, r2}
-	stmia r4, {r0, r1, r2}
-	ldrb r0, [sl, #0x2bc]
-	add r4, sl, #0x200
-	mov r6, #0
-	cmp r0, #0
-	moveq sb, #6
-	movne sb, #0xf
-	ldrsh r7, [r4, #0xbe]
-	mov r5, r6
-	mov r8, #0x12
-	b _022EBC9C
-_022EBC64:
-	add r0, sl, r6, lsl #1
-	add r0, r0, #0x200
-	ldrsh r1, [r0, #0xca]
-	cmp r1, #0
-	addle r0, sl, r6, lsl #2
-	strle r5, [r0, #0x2dc]
-	ble _022EBC94
-	mul r0, r1, r8
-	mov r1, sb
-	bl MemAlloc
-	add r1, sl, r6, lsl #2
-	str r0, [r1, #0x2dc]
-_022EBC94:
-	add r6, r6, #1
-	add r7, r7, #1
-_022EBC9C:
-	ldrsh r0, [r4, #0xc0]
-	cmp r6, r0
-	blt _022EBC64
-	mov r1, #0
-	b _022EBCC0
-_022EBCB0:
-	add r0, sl, r6, lsl #2
-	str r1, [r0, #0x2dc]
-	add r6, r6, #1
-	add r7, r7, #1
-_022EBCC0:
-	cmp r6, #2
-	blt _022EBCB0
-	add r4, sl, #0x200
-	mov r7, #0
-	ldrsh r8, [r4, #0xbe]
-	mov r6, r7
-	ldr r5, _022EBEA4 ; =ov11_02324CBC
-	mov fp, #0x1c
-	b _022EBD54
-_022EBCE4:
-	ldrb r0, [sl, #0x2bc]
-	cmp r0, #0
-	ldr r0, [r5]
-	bne _022EBD00
-	mla r0, r8, fp, r0
-	bl sub_0200B500
-	b _022EBD10
-_022EBD00:
-	add r1, r0, #0x38
-	mov r0, #0x1c
-	mla r0, r8, r0, r1
-	bl sub_0200B500
-_022EBD10:
-	add r1, sl, r7, lsl #2
-	str r0, [r1, #0x2ec]
-	add r0, sl, r7, lsl #1
-	add r0, r0, #0x200
-	ldrsh r0, [r0, #0xca]
-	cmp r0, #0
-	addle r0, sl, r7, lsl #2
-	strle r6, [r0, #0x2e4]
-	ble _022EBD4C
-	ldrsh r0, [r4, #0xd0]
-	mov r1, sb
-	mov r0, r0, lsl #7
-	bl MemAlloc
-	add r1, sl, r7, lsl #2
-	str r0, [r1, #0x2e4]
-_022EBD4C:
-	add r7, r7, #1
-	add r8, r8, #1
-_022EBD54:
-	ldrsh r0, [r4, #0xc0]
-	cmp r7, r0
-	blt _022EBCE4
-	mov r1, #0
-	b _022EBD78
-_022EBD68:
-	add r0, sl, r7, lsl #2
-	str r1, [r0, #0x2ec]
-	str r1, [r0, #0x2e4]
-	add r7, r7, #1
-_022EBD78:
-	cmp r7, #2
-	blt _022EBD68
-	ldr r0, [sl, #0x2d4]
-	cmp r0, #0
-	moveq r0, #0
-	beq _022EBDA4
-	add r0, sl, #0x200
-	ldrsh r0, [r0, #0xce]
-	mov r1, sb
-	mov r0, r0, lsl #8
-	bl MemAlloc
-_022EBDA4:
-	str r0, [sl, #0x2d8]
-	mov r0, sl
-	bl ov11_022EBF60
-	mov r2, #0
-	strh r2, [sl]
-	strb r2, [sl, #0x1c0]
-	strb r2, [sl, #0x2ba]
-	sub r1, r2, #1
-	add r0, sl, #0x100
-	strh r1, [r0, #0xbe]
-	str r2, [sl, #0x1f0]
-	strb r2, [sl, #0x1e0]
-	strb r2, [sl, #0x1e1]
-	strb r2, [sl, #0x1e2]
-	strb r2, [sl, #0x1e3]
-	strb r2, [sl, #0x1ee]
-	str r2, [sl, #0x1f4]
-	strb r2, [sl, #0x1f8]
-	strb r2, [sl, #0x1f9]
-	strb r2, [sl, #0x1fa]
-	strb r2, [sl, #0x1fb]
-	strb r2, [sl, #0x1bc]
-	add r0, sl, #4
-	mov r3, r2
-_022EBE04:
-	strh r3, [r0]
-	strh r3, [r0, #2]
-	add r2, r2, #1
-	str r3, [r0, #8]
-	str r3, [r0, #4]
-	cmp r2, #0x10
-	add r0, r0, #0xc
-	blt _022EBE04
-	add r2, sl, #0xc4
-	mov r4, #0
-	mov r0, #0x2c
-_022EBE30:
-	mul r1, r3, r0
-	strb r4, [r2, r1]
-	add r1, r2, r1
-	strb r4, [r1, #1]
-	strh r4, [r1, #2]
-	strh r4, [r1, #4]
-	str r4, [r1, #0x10]
-	str r4, [r1, #0x18]
-	str r4, [r1, #0x14]
-	str r4, [r1, #0x20]
-	str r4, [r1, #0x1c]
-	add r3, r3, #1
-	str r4, [r1, #0x24]
-	str r4, [r1, #0x28]
-	cmp r3, #4
-	blt _022EBE30
-	ldr r0, _022EBEA8 ; =ov11_02320BE4
-	ldr r2, [r0, #0x14]
-	ldr r1, [r0, #0x18]
-	str r2, [sp]
-	str r1, [sp, #4]
-_022EBE84:
-	add r0, sl, r4, lsl #3
-	str r2, [r0, #0x200]
-	add r4, r4, #1
-	str r1, [r0, #0x204]
-	cmp r4, #2
-	blt _022EBE84
-	add sp, sp, #8
-	ldmia sp!, {r3, r4, r5, r6, r7, r8, sb, sl, fp, pc}
-	.align 2, 0
-_022EBEA4: .word ov11_02324CBC
-_022EBEA8: .word ov11_02320BE4
-	arm_func_end ov11_022EBC18
-
 	arm_func_start ov11_022EBEAC
 ov11_022EBEAC: ; 0x022EBEAC
 	stmdb sp!, {r4, r5, r6, r7, r8, lr}
diff --git a/include/overlay_11_022EBB40.h b/include/overlay_11_022EBB40.h
index d1c9299a..6b92044c 100644
--- a/include/overlay_11_022EBB40.h
+++ b/include/overlay_11_022EBB40.h
@@ -1,6 +1,12 @@
 #ifndef PMDSKY_OVERLAY_11_022EBB40_H
 #define PMDSKY_OVERLAY_11_022EBB40_H
 
+struct iovec
+{
+    void* iov_base;
+    u32 iov_len;
+};
+
 #define BG_NAME_LEN 8
 
 struct bg_list_entry_sub_struct {
@@ -17,6 +23,213 @@ struct bg_list_entry {
     struct bg_list_entry_sub_struct others_bpa[BPA_MAX_ENTRIES];
 };
 
+#define UNK_0_ARR_COUNT 16 // Was 14 in Red
+#define UNK_E0_ARR_COUNT 32
+#define UNK_3E0_ARR_COUNT 4 // Was 2 in Red
+#define NUM_LAYERS 2
+
+typedef struct PixelPos
+{
+    /* 0x0 */ s32 x;
+    /* 0x4 */ s32 y;
+} PixelPos;
+
+typedef struct SubStruct_0
+{
+    s16 unk0;
+    s16 unk2;
+    const void *unk4;
+    const void *unk8;
+    //u8 fillC; // Filler byte removed in Sky, present in Red
+} SubStruct_0;
+
+// Was 0x24 in Red...
+typedef struct SubStruct_3E0
+{
+    u8 unk0;
+    u8 unk1;
+    s16 unk2;
+    s16 unk4;
+    struct iovec bpaFile;
+    //const struct BpaHeader *unkC; hm...
+    const void *unk10;
+    const void *unk14;
+    const void *unk18;
+    const void *unk1C;
+    void *unk20;
+    u32 unk24;
+    u32 unk28;
+} SubStruct_3E0;
+
+// size: 0x18?
+typedef struct SubStruct_52C
+{
+    u8 unk0; // 0x52C
+    s16 unk2; // 0x52E
+    s16 unk4; // 0x530
+    s16 unk6; // 0x532
+    s16 unk8; // 0x534
+    s16 unkA; // 0x536
+    s16 unkC; // numLayers
+    s16 unkE[2]; // 0x53A
+    s16 unk12; // 0x53E
+    s16 unk14;
+    s16 unk16;
+    void *unk18; // Maybe void (*unk14)(void *, const void *, BmaHeader *, s32); // TODO: fix void * to proper ptr types 0x540
+} SubStruct_52C;
+
+#define CHUNK_DIMENSIONS_3x3 2
+
+// size: 0x55C
+typedef struct GroundBg
+{
+    u16 newUnk0; // Not present in Red
+    SubStruct_0 unk0[UNK_0_ARR_COUNT];
+    SubStruct_3E0 unk3E0[UNK_3E0_ARR_COUNT]; // 0xc4
+    u8 unk174; // 0x174
+    u8 unk175;
+    u8 unk176;
+    u8 unk177;
+    u8 unk178;
+    u8 unk179;
+    u8 unk17A;
+    u8 unk17B;
+    u8 unk17C;
+    u8 unk17D;
+    u8 unk17E;
+    u8 unk17F;
+    u8 unk180;
+    u8 unk181;
+    u8 unk182;
+    u8 unk183;
+    u8 unk184;
+    u8 unk185;
+    u8 unk186;
+    u8 unk187;
+    u8 unk188;
+    u8 unk189;
+    u8 unk18A;
+    u8 unk18B;
+    u8 unk18C;
+    u8 unk18D;
+    u8 unk18E;
+    u8 unk18F;
+    u8 unk190;
+    u8 unk191;
+    u8 unk192;
+    u8 unk193;
+    u8 unk194;
+    u8 unk195;
+    u8 unk196;
+    u8 unk197;
+    u8 unk198;
+    u8 unk199;
+    u8 unk19A;
+    u8 unk19B;
+    u8 unk19C;
+    u8 unk19D;
+    u8 unk19E;
+    u8 unk19F;
+    u8 unk1A0;
+    u8 unk1A1;
+    u8 unk1A2;
+    u8 unk1A3;
+    u8 unk1A4;
+    u8 unk1A5;
+    u8 unk1A6;
+    u8 unk1A7;
+    u8 unk1A8;
+    u8 unk1A9;
+    u8 unk1AA;
+    u8 unk1AB;
+    u8 unk1AC;
+    u8 unk1AD;
+    u8 unk1AE;
+    u8 unk1AF;
+    u8 unk1B0;
+    u8 unk1B1;
+    u8 unk1B2;
+    u8 unk1B3;
+    u8 unk1B4;
+    u8 unk1B5;
+    u8 unk1B6;
+    u8 unk1B7;
+    u8 unk1B8;
+    u8 unk1B9;
+    u8 unk1BA;
+    u8 unk1BB;
+    u8 unk1BC;
+    u8 unk1BD;
+    s16 unk1BE;
+    u8 unk1C0;
+    u8 unk1C1;
+    u8 unk1C2;
+    u8 unk1C3;
+    u8 unk1C4;
+    u8 unk1C5;
+    u8 unk1C6;
+    u8 unk1C7;
+    u8 unk1C8;
+    u8 unk1C9;
+    u8 unk1CA;
+    u8 unk1CB;
+    u8 unk1CC;
+    u8 unk1CD;
+    u8 unk1CE;
+    u8 unk1CF;
+    u8 unk1D0;
+    u8 unk1D1;
+    u8 unk1D2;
+    u8 unk1D3;
+    u8 unk1D4;
+    u8 unk1D5;
+    u8 unk1D6;
+    u8 unk1D7;
+    u8 unk1D8;
+    u8 unk1D9;
+    u8 unk1DA;
+    u8 unk1DB;
+    u8 unk1DC;
+    u8 unk1DD;
+    u8 unk1DE;
+    u8 unk1DF;
+    u8 unk1E0;
+    u8 unk1E1;
+    u8 unk1E2;
+    u8 unk1E3;
+    u8 unk1E4;
+    u8 unk1E5;
+    u8 unk1E6;
+    u8 unk1E7;
+    u8 unk1E8;
+    u8 unk1E9;
+    u8 unk1EA;
+    u8 unk1EB;
+    u8 unk1EC;
+    u8 unk1ED;
+    u8 unk1EE;
+    u8 unk1EF;
+    s32 unk1F0;
+    s32 unk1F4;
+    u8 unk1F8;
+    u8 unk1F9;
+    u8 unk1FA;
+    u8 unk1FB;
+    u8 unk1FC;
+    u8 unk1FD;
+    u8 unk1FE;
+    u8 unk1FF;
+    PixelPos cameraPixelPosition[NUM_LAYERS]; // 0x200
+    u8 fillerForNow2[170];
+    u8 unk2BA;
+    SubStruct_52C unk52C; // 2bc
+    u16 *unk2D8;
+    u16 *unk2DC[2];
+    u16 *unk2E4[2];
+    u16 *unk2EC[2];
+} GroundBg;
+
 void LoadBackgroundAttributes(struct bg_list_entry* entry, int bgId);
+void ov11_022EBC18(GroundBg *groundBg, const SubStruct_52C *a1);
 
 #endif //PMDSKY_OVERLAY_11_022EBB40_H
diff --git a/main.lsf b/main.lsf
index 97e44ecf..e757552b 100644
--- a/main.lsf
+++ b/main.lsf
@@ -185,7 +185,7 @@ Overlay OVY_11
 	After OVY_10
 	Object asm/overlay_11.o
 	Object src/overlay_11_022EBB40.o
-	Object asm/overlay_11_022EBC18.o
+	Object asm/overlay_11_022EBEAC.o
 }
 Overlay OVY_12
 {
diff --git a/src/overlay_11_022EBB40.c b/src/overlay_11_022EBB40.c
index 19fdf8b1..fa7b0df9 100644
--- a/src/overlay_11_022EBB40.c
+++ b/src/overlay_11_022EBB40.c
@@ -2,6 +2,7 @@
 #include "file_rom.h"
 
 extern void FileClose(struct file_stream* file);
+extern void* MemAlloc(u32 len, u32 flags);
 
 extern const char ov11_02320C44[];
 
@@ -32,3 +33,114 @@ void LoadBackgroundAttributes(struct bg_list_entry* entry, int bgId)
     FileClose(&file);
     FileRom_StopDataTransfer();
 }
+
+void ov11_022EBF60(GroundBg *groundBg);
+void *sub_0200B500(void *unk);
+
+struct UnkStruct_2324CBC
+{
+    u8 fill0[0x1C];
+};
+
+extern struct UnkStruct_2324CBC *ov11_02324CBC;
+
+struct ConstFileData
+{
+    u8 otherData[20];
+    const PixelPos sPositionZero;
+};
+
+extern const struct ConstFileData ov11_02320BE4;
+
+// GroundBg_Init?
+void ov11_022EBC18(GroundBg *groundBg, const SubStruct_52C *a1)
+{
+    SubStruct_0 *unk0Ptr;
+    s32 id, unk0Id, unk3E0Id;
+    s32 i;
+    s32 id2;
+    s32 memGroup;
+
+    groundBg->unk52C = *a1;
+    memGroup = (groundBg->unk52C.unk0 == 0) ? 6 : 15;
+    id2 = groundBg->unk52C.unk2;
+    for (id = 0; id < groundBg->unk52C.unk4; id++, id2++) {
+        if (groundBg->unk52C.unkE[id] > 0) {
+            groundBg->unk2DC[id] = MemAlloc(groundBg->unk52C.unkE[id] * 18u, memGroup);
+        }
+        else {
+            groundBg->unk2DC[id] = NULL;
+        }
+    }
+    for (; id < NUM_LAYERS; id++, id2++) {
+        groundBg->unk2DC[id] = NULL;
+    }
+
+    id = groundBg->unk52C.unk2;
+    for (id2 = 0; id2 < groundBg->unk52C.unk4; id2++, id++) {
+
+        if (groundBg->unk52C.unk0 == 0) {
+            groundBg->unk2EC[id2] = sub_0200B500(&ov11_02324CBC[id]);
+        }
+        else {
+            struct UnkStruct_2324CBC *ptr = ov11_02324CBC;
+            ptr += 2;
+            groundBg->unk2EC[id2] = sub_0200B500(&ptr[id]);
+        }
+
+        if (groundBg->unk52C.unkE[id2] > 0) {
+            groundBg->unk2E4[id2] = MemAlloc(groundBg->unk52C.unk14 * 128, memGroup);
+        }
+        else {
+            groundBg->unk2E4[id2] = NULL;
+        }
+    }
+    for (; id2 < 2; id2++) {
+        groundBg->unk2EC[id2] = NULL;
+        groundBg->unk2E4[id2] = NULL;
+    }
+
+    groundBg->unk2D8 = (groundBg->unk52C.unk18 == 0) ? NULL : MemAlloc(groundBg->unk52C.unk12 * 256, memGroup);
+    ov11_022EBF60(groundBg);
+    groundBg->newUnk0 = 0;
+    groundBg->unk1C0 = 0;
+    groundBg->unk2BA = 0;
+    groundBg->unk1BE = -1;
+    groundBg->unk1F0 = 0;
+    groundBg->unk1E0 = 0;
+    groundBg->unk1E1 = 0;
+    groundBg->unk1E2 = 0;
+    groundBg->unk1E3 = 0;
+    groundBg->unk1EE = 0;
+    groundBg->unk1F4 = 0;
+    groundBg->unk1F8 = 0;
+    groundBg->unk1F9 = 0;
+    groundBg->unk1FA = 0;
+    groundBg->unk1FB = 0;
+    groundBg->unk1BC = 0;
+
+    unk0Ptr = &groundBg->unk0[0];
+    for (unk0Id = 0; unk0Id < UNK_0_ARR_COUNT; unk0Id++, unk0Ptr++) {
+        unk0Ptr->unk0 = 0;
+        unk0Ptr->unk2 = 0;
+        unk0Ptr->unk4 = unk0Ptr->unk8 = 0;
+    }
+
+    for (unk3E0Id = 0; unk3E0Id < UNK_3E0_ARR_COUNT; unk3E0Id++) {
+        SubStruct_3E0 *unkPtr = &groundBg->unk3E0[unk3E0Id];
+        unkPtr->unk0 = 0;
+        unkPtr->unk1 = 0;
+        unkPtr->unk2 = 0;
+        unkPtr->unk4 = 0;
+        unkPtr->unk10 = 0;
+        unkPtr->unk18 = 0;
+        unkPtr->unk14 = 0;
+        unkPtr->unk20 = 0;
+        unkPtr->unk1C = 0;
+        unkPtr->unk28 = unkPtr->unk24 = 0;
+    }
+
+    for (i = 0; i < NUM_LAYERS; i++) {
+        groundBg->cameraPixelPosition[i] = ov11_02320BE4.sPositionZero;
+    }
+}