diff --git a/asm/link_rfu.s b/asm/link_rfu.s
index da233b86b..baddaf055 100644
--- a/asm/link_rfu.s
+++ b/asm/link_rfu.s
@@ -5,100 +5,6 @@
 
 	.text
 
-	thumb_func_start sub_800F638
-sub_800F638: @ 800F638
-	push {r4-r7,lr}
-	mov r7, r10
-	mov r6, r9
-	mov r5, r8
-	push {r5-r7}
-	ldr r0, =gUnknown_03005000
-	ldr r2, [r0, 0x70]
-	mov r10, r2
-	movs r5, 0
-	adds r2, r0, 0
-	adds r2, 0x6E
-	ldrh r3, [r2]
-	cmp r5, r3
-	bge _0800F6D4
-	mov r9, r0
-	ldr r0, =gUnknown_03000D90
-	mov r8, r0
-_0800F65A:
-	movs r0, 0x1
-	ands r0, r1
-	lsrs r7, r1, 1
-	adds r6, r5, 0x1
-	cmp r0, 0
-	bne _0800F6C8
-	ldr r1, =0xffff8900
-	adds r0, r1, 0
-	adds r1, r5, 0
-	orrs r1, r0
-	mov r2, r8
-	strh r1, [r2]
-	movs r4, 0
-	lsls r0, r5, 1
-	ldr r3, =gUnknown_03000D80
-	mov r12, r3
-	adds r0, r5
-	lsls r0, 2
-	mov r1, r10
-	adds r2, r0, r1
-	mov r3, r8
-	adds r3, 0x2
-_0800F686:
-	ldrb r1, [r2, 0x1]
-	lsls r1, 8
-	ldrb r0, [r2]
-	orrs r0, r1
-	strh r0, [r3]
-	adds r2, 0x2
-	adds r3, 0x2
-	adds r4, 0x1
-	cmp r4, 0x6
-	ble _0800F686
-	movs r4, 0
-	ldr r2, =gUnknown_03000D90
-	ldr r1, =gUnknown_03000D80
-_0800F6A0:
-	ldrh r0, [r2]
-	lsrs r0, 8
-	strb r0, [r1, 0x1]
-	ldrh r0, [r2]
-	strb r0, [r1]
-	adds r2, 0x2
-	adds r1, 0x2
-	adds r4, 0x1
-	cmp r4, 0x6
-	ble _0800F6A0
-	ldr r0, =gUnknown_03005000+0x9E8
-	mov r1, r12
-	bl sub_800D888
-	movs r1, 0x1
-	lsls r1, r5
-	mov r2, r9
-	ldr r0, [r2, 0x78]
-	orrs r0, r1
-	str r0, [r2, 0x78]
-_0800F6C8:
-	adds r1, r7, 0
-	adds r5, r6, 0
-	ldr r3, =gUnknown_03005000+0x6E
-	ldrh r3, [r3]
-	cmp r5, r3
-	blt _0800F65A
-_0800F6D4:
-	pop {r3-r5}
-	mov r8, r3
-	mov r9, r4
-	mov r10, r5
-	pop {r4-r7}
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end sub_800F638
-
 	thumb_func_start sub_800F6FC
 sub_800F6FC: @ 800F6FC
 	push {lr}
diff --git a/include/link_rfu.h b/include/link_rfu.h
index 80d2689ed..6e8346a88 100644
--- a/include/link_rfu.h
+++ b/include/link_rfu.h
@@ -96,9 +96,9 @@ struct UnkRfuStruct_1 {
 struct UnkRfuStruct_2_Sub_6c {
     /* 0x00 */ u16 unk_00;
     /* 0x02 */ u16 unk_02;
-    /* 0x04 */ u32 unk_04;
+    /* 0x04 */ u8 *unk_04;
     /* 0x08 */ u32 unk_08;
-    /* 0x0c */ u8 filler_0c[4];
+    /* 0x0c */ u32 unk_0c;
     /* 0x10 */ u8 unk_10;
     /* 0x11 */ u8 unk_11;
     /* 0x12 */ u8 unk_12;
diff --git a/src/link_rfu.c b/src/link_rfu.c
index f8a978e1f..10a6a7914 100644
--- a/src/link_rfu.c
+++ b/src/link_rfu.c
@@ -3191,3 +3191,128 @@ bool32 sub_800F4F0(void)
     }
     return sub_800F0B8();
 }
+
+#ifdef NONMATCHING
+void sub_800F638(u8 unused, u32 flags)
+{
+    int i;
+    int j;
+
+    u8 *r10 = gUnknown_03005000.unk_6c.unk_04;
+    for (i = 0; i < gUnknown_03005000.unk_6c.unk_02; i++)
+    {
+        if (!(flags & 1))
+        {
+            gUnknown_03000D90[0] = (~0x76ff) | i;
+            for (j = 0; j < 7; j++)
+            {
+                gUnknown_03000D90[j + 1] = (r10[12 * i + (j << 1) + 1] << 8) | r10[12 * i + (j << 1) + 0];
+            }
+            for (j = 0; j < 7; j++)
+            // This should be an ascending loop.
+            // GCC compiles this as descending.
+            {
+                gUnknown_03000D80[2 * j + 1] = gUnknown_03000D90[j] >> 8;
+                gUnknown_03000D80[2 * j + 0] = gUnknown_03000D90[j];
+            }
+            sub_800D888(&gUnknown_03005000.unk_9e8, gUnknown_03000D80);
+            gUnknown_03005000.unk_6c.unk_0c |= (1 << i);
+        }
+        flags >>= 1;
+    }
+}
+#else
+__attribute__((naked)) void sub_800F638(u8 unused, u32 flags)
+{
+    asm_unified("\tpush {r4-r7,lr}\n"
+                    "\tmov r7, r10\n"
+                    "\tmov r6, r9\n"
+                    "\tmov r5, r8\n"
+                    "\tpush {r5-r7}\n"
+                    "\tldr r0, =gUnknown_03005000\n"
+                    "\tldr r2, [r0, 0x70]\n"
+                    "\tmov r10, r2\n"
+                    "\tmovs r5, 0\n"
+                    "\tadds r2, r0, 0\n"
+                    "\tadds r2, 0x6E\n"
+                    "\tldrh r3, [r2]\n"
+                    "\tcmp r5, r3\n"
+                    "\tbge _0800F6D4\n"
+                    "\tmov r9, r0\n"
+                    "\tldr r0, =gUnknown_03000D90\n"
+                    "\tmov r8, r0\n"
+                    "_0800F65A:\n"
+                    "\tmovs r0, 0x1\n"
+                    "\tands r0, r1\n"
+                    "\tlsrs r7, r1, 1\n"
+                    "\tadds r6, r5, 0x1\n"
+                    "\tcmp r0, 0\n"
+                    "\tbne _0800F6C8\n"
+                    "\tldr r1, =0xffff8900\n"
+                    "\tadds r0, r1, 0\n"
+                    "\tadds r1, r5, 0\n"
+                    "\torrs r1, r0\n"
+                    "\tmov r2, r8\n"
+                    "\tstrh r1, [r2]\n"
+                    "\tmovs r4, 0\n"
+                    "\tlsls r0, r5, 1\n"
+                    "\tldr r3, =gUnknown_03000D80\n"
+                    "\tmov r12, r3\n"
+                    "\tadds r0, r5\n"
+                    "\tlsls r0, 2\n"
+                    "\tmov r1, r10\n"
+                    "\tadds r2, r0, r1\n"
+                    "\tmov r3, r8\n"
+                    "\tadds r3, 0x2\n"
+                    "_0800F686:\n"
+                    "\tldrb r1, [r2, 0x1]\n"
+                    "\tlsls r1, 8\n"
+                    "\tldrb r0, [r2]\n"
+                    "\torrs r0, r1\n"
+                    "\tstrh r0, [r3]\n"
+                    "\tadds r2, 0x2\n"
+                    "\tadds r3, 0x2\n"
+                    "\tadds r4, 0x1\n"
+                    "\tcmp r4, 0x6\n"
+                    "\tble _0800F686\n"
+                    "\tmovs r4, 0\n"
+                    "\tldr r2, =gUnknown_03000D90\n"
+                    "\tldr r1, =gUnknown_03000D80\n"
+                    "_0800F6A0:\n"
+                    "\tldrh r0, [r2]\n"
+                    "\tlsrs r0, 8\n"
+                    "\tstrb r0, [r1, 0x1]\n"
+                    "\tldrh r0, [r2]\n"
+                    "\tstrb r0, [r1]\n"
+                    "\tadds r2, 0x2\n"
+                    "\tadds r1, 0x2\n"
+                    "\tadds r4, 0x1\n"
+                    "\tcmp r4, 0x6\n"
+                    "\tble _0800F6A0\n"
+                    "\tldr r0, =gUnknown_03005000+0x9E8\n"
+                    "\tmov r1, r12\n"
+                    "\tbl sub_800D888\n"
+                    "\tmovs r1, 0x1\n"
+                    "\tlsls r1, r5\n"
+                    "\tmov r2, r9\n"
+                    "\tldr r0, [r2, 0x78]\n"
+                    "\torrs r0, r1\n"
+                    "\tstr r0, [r2, 0x78]\n"
+                    "_0800F6C8:\n"
+                    "\tadds r1, r7, 0\n"
+                    "\tadds r5, r6, 0\n"
+                    "\tldr r3, =gUnknown_03005000+0x6E\n"
+                    "\tldrh r3, [r3]\n"
+                    "\tcmp r5, r3\n"
+                    "\tblt _0800F65A\n"
+                    "_0800F6D4:\n"
+                    "\tpop {r3-r5}\n"
+                    "\tmov r8, r3\n"
+                    "\tmov r9, r4\n"
+                    "\tmov r10, r5\n"
+                    "\tpop {r4-r7}\n"
+                    "\tpop {r0}\n"
+                    "\tbx r0\n"
+                    "\t.pool");
+}
+#endif