through sub_800C054

asm/link.s

@@ -7,167 +7,6 @@
 
 // RFU; bss indicates that no file boundary exists here
 
-	thumb_func_start sub_800C000
-sub_800C000: @ 800C000
-	push {r4,r5,lr}
-	ldr r2, =gUnknown_03004140
-	movs r0, 0
-	strb r0, [r2, 0x5]
-	strb r0, [r2, 0x4]
-	movs r1, 0xFF
-	strb r1, [r2, 0x6]
-	strb r0, [r2, 0x7]
-	strb r0, [r2, 0x10]
-	strb r0, [r2, 0xC]
-	adds r1, r2, 0
-	adds r1, 0x24
-	strb r0, [r1]
-	adds r1, 0xC
-	strb r0, [r1]
-	movs r3, 0
-	adds r5, r2, 0
-	adds r5, 0x28
-	movs r4, 0
-	adds r2, 0x34
-_0800C028:
-	lsls r1, r3, 1
-	adds r0, r1, r5
-	strh r4, [r0]
-	adds r1, r2
-	strh r4, [r1]
-	adds r0, r3, 0x1
-	lsls r0, 24
-	lsrs r3, r0, 24
-	cmp r3, 0x3
-	bls _0800C028
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end sub_800C000
-
-	thumb_func_start sub_800C048
-sub_800C048: @ 800C048
-	ldr r1, =gUnknown_03004140
-	movs r0, 0x15
-	strb r0, [r1, 0x4]
-	bx lr
-	.pool
-	thumb_func_end sub_800C048
-
-	thumb_func_start sub_800C054
-sub_800C054: @ 800C054
-	push {r4-r7,lr}
-	mov r7, r8
-	push {r7}
-	adds r6, r3, 0
-	lsls r0, 24
-	lsrs r5, r0, 24
-	lsls r1, 16
-	lsrs r7, r1, 16
-	lsls r2, 16
-	lsrs r2, 16
-	mov r8, r2
-	ldr r1, =gUnknown_03004140
-	ldrb r0, [r1, 0x4]
-	cmp r0, 0
-	beq _0800C090
-	cmp r0, 0x8
-	bne _0800C07A
-	cmp r5, 0x1
-	beq _0800C090
-_0800C07A:
-	movs r0, 0x1
-	strh r0, [r1, 0x14]
-	movs r0, 0xF3
-	movs r1, 0x1
-	bl sub_800D30C
-	movs r0, 0x1
-	b _0800C122
-	.pool
-_0800C090:
-	bl rfu_getMasterSlave
-	lsls r0, 24
-	cmp r0, 0
-	bne _0800C0B0
-	ldr r1, =gUnknown_03004140
-	movs r0, 0x2
-	strh r0, [r1, 0x14]
-	movs r0, 0xF3
-	movs r1, 0x1
-	bl sub_800D30C
-	movs r0, 0x2
-	b _0800C122
-	.pool
-_0800C0B0:
-	movs r2, 0
-	ldrh r0, [r6]
-	ldr r4, =0x0000ffff
-	adds r1, r6, 0x2
-	ldr r3, =gUnknown_03004140
-	cmp r0, r4
-	beq _0800C0D0
-_0800C0BE:
-	adds r0, r2, 0x1
-	lsls r0, 24
-	lsrs r2, r0, 24
-	cmp r2, 0xF
-	bhi _0800C0D0
-	ldrh r0, [r1]
-	adds r1, 0x2
-	cmp r0, r4
-	bne _0800C0BE
-_0800C0D0:
-	cmp r2, 0x10
-	bne _0800C0EC
-	movs r0, 0x4
-	strh r0, [r3, 0x14]
-	movs r0, 0xF3
-	movs r1, 0x1
-	bl sub_800D30C
-	movs r0, 0x4
-	b _0800C122
-	.pool
-_0800C0EC:
-	cmp r5, 0x1
-	bls _0800C0FA
-	movs r0, 0x1
-	strb r0, [r3, 0x7]
-	movs r5, 0x1
-	movs r7, 0
-	b _0800C0FE
-_0800C0FA:
-	movs r0, 0
-	strb r0, [r3, 0x7]
-_0800C0FE:
-	cmp r5, 0
-	beq _0800C108
-	movs r0, 0x5
-	strb r0, [r3, 0x4]
-	b _0800C116
-_0800C108:
-	movs r0, 0x9
-	strb r0, [r3, 0x4]
-	ldrb r0, [r3, 0xB]
-	cmp r0, 0
-	beq _0800C116
-	movs r0, 0x2
-	strb r0, [r3, 0xB]
-_0800C116:
-	strb r5, [r3, 0x6]
-	strh r7, [r3, 0x1A]
-	mov r0, r8
-	strh r0, [r3, 0x26]
-	str r6, [r3, 0x20]
-	movs r0, 0
-_0800C122:
-	pop {r3}
-	mov r8, r3
-	pop {r4-r7}
-	pop {r1}
-	bx r1
-	thumb_func_end sub_800C054
-
 	thumb_func_start sub_800C12C
 sub_800C12C: @ 800C12C
 	push {r4-r7,lr}
@@ -1255,7 +1094,7 @@ _0800CA0C:
 _0800CA18:
 	cmp r6, 0
 	bne _0800CA3C
-	ldr r4, =gUnknown_03004150
+	ldr r4, =gUnknown_03004140+0x10
 	mov r0, sp
 	adds r1, r4, 0
 	bl rfu_getConnectParentStatus
@@ -1293,7 +1132,7 @@ _0800CA60:
 	beq _0800CA66
 	b _0800CC8A
 _0800CA66:
-	ldr r4, =gUnknown_03004150
+	ldr r4, =gUnknown_03004140+0x10
 	mov r0, sp
 	adds r1, r4, 0
 	bl rfu_getConnectParentStatus

include/librfu.h

@@ -149,3 +149,4 @@ u32 rfu_REQBN_softReset_and_checkID(void);
 void rfu_REQ_sendData(u8);
 void rfu_setMSCCallback(void (*func)(u16));
 void rfu_setREQCallback(void (*func)(u16, u16));
+bool8 rfu_getMasterSlave(void);

include/link_rfu.h

@@ -27,11 +27,22 @@ struct UnkRfuStruct_1 {
     u8 unk_0b;
     u8 unk_0c;
     u8 unk_0d;
-    u8 filler_0e[10];
+    u8 filler_0e[2];
+    u8 unk_10;
+    u8 filler_11[3];
+    u16 unk_14;
+    u8 filler_16[2];
     u16 unk_18;
-    u8 filler_1a[0x18];
+    u16 unk_1a;
+    u8 filler_1c[4];
+    u16 *unk_20;
+    u8 unk_24;
+    u16 unk_26;
+    u16 unk_28[4];
+    u8 unk_30;
+    // aligned
     u16 unk_32;
-    u8 filler_34[8];
+    u16 unk_34[4];
     struct UnkLinkRfuStruct_02022B2C *unk_3c;
     void (*unk_40)(u8);
     void (*unk_44)(void);

src/link.c

@@ -174,6 +174,8 @@ void sub_800CEB0(u16 unk0);
 void sub_800C7B4(u16 unk0, u16 unk1);
 void sub_800C000(void);
 
+void sub_800D30C(u8 a0, u8 a1);
+
 // .rodata
 
 ALIGNED(4) const u16 gWirelessLinkDisplayPal[] = INCBIN_U16("graphics/interface/wireless_link_display.gbapal");
@@ -2524,3 +2526,86 @@ void sub_800BFCC(struct UnkLinkRfuStruct_02022B2C *unk0)
         gUnknown_03004140.unk_0b = 1;
     }
 }
+
+void sub_800C000(void)
+{
+    u8 i;
+
+    gUnknown_03004140.unk_05 = 0;
+    gUnknown_03004140.unk_04 = 0;
+    gUnknown_03004140.unk_06 = -1;
+    gUnknown_03004140.unk_07 = 0;
+    gUnknown_03004140.unk_10 = 0;
+    gUnknown_03004140.unk_0c = 0;
+    gUnknown_03004140.unk_24 = 0;
+    gUnknown_03004140.unk_30 = 0;
+    for (i = 0; i < 4; i++)
+    {
+        gUnknown_03004140.unk_28[i] = 0;
+        gUnknown_03004140.unk_34[i] = 0;
+    }
+}
+
+void sub_800C048(void)
+{
+    gUnknown_03004140.unk_04 = 0x15;
+}
+
+u8 sub_800C054(u8 r5, u16 r7, u16 r8, u16 *r6)
+{
+    u8 i;
+    u16 *buffer;
+
+    if (gUnknown_03004140.unk_04 != 0 && (gUnknown_03004140.unk_04 != 0x08 || r5 != 1))
+    {
+        gUnknown_03004140.unk_14 = 1;
+        sub_800D30C(0xf3, 0x01);
+        return 1;
+    }
+    if (!rfu_getMasterSlave())
+    {
+        gUnknown_03004140.unk_14 = 2;
+        sub_800D30C(0xf3, 0x01);
+        return 2;
+    }
+    for (i = 0, buffer = r6; i < 16; i++)
+    {
+        if (*buffer++ == 0xFFFF)
+        {
+            break;
+        }
+    }
+    if (i == 16)
+    {
+        gUnknown_03004140.unk_14 = 4;
+        sub_800D30C(0xf3, 0x01);
+        return 4;
+    }
+    if (r5 > 1)
+    {
+        gUnknown_03004140.unk_07 = 1;
+        r5 = 1;
+        r7 = 0;
+    }
+    else
+    {
+        gUnknown_03004140.unk_07 = 0;
+    }
+    if (r5 != 0)
+    {
+        gUnknown_03004140.unk_04 = 5;
+    }
+    else
+    {
+        gUnknown_03004140.unk_04 = 9;
+        if (gUnknown_03004140.unk_0b)
+        {
+            gUnknown_03004140.unk_0b = 2;
+        }
+    }
+    gUnknown_03004140.unk_06 = r5;
+    gUnknown_03004140.unk_1a = r7;
+    gUnknown_03004140.unk_26 = r8;
+    gUnknown_03004140.unk_20 = r6;
+    return 0;
+}

sym_common.txt

@@ -14,10 +14,10 @@ gUnknown_03002F70: @ 3002F70
 	.include "link.o"
 
 gUnknown_03004140: @ 3004140
-	.space 0x10
+	.space 0x48
 
-gUnknown_03004150: @ 3004150
+gUnknown_03004188: @ 3004150
-	.space 0x40
+	.space 0x8
 
 gUnknown_03004190: @ 3004190
 	.space 0xE70