diff --git a/asm/battle_tower.s b/asm/battle_tower.s
index 122d9d27c..c21a706f4 100755
--- a/asm/battle_tower.s
+++ b/asm/battle_tower.s
@@ -5264,7 +5264,7 @@ _08164D14:
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08164DB0
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	bne _08164DB0
@@ -5302,7 +5302,7 @@ _08164DB6:
 	thumb_func_start sub_8164DCC
 sub_8164DCC: @ 8164DCC
 	push {lr}
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08164DDA
diff --git a/asm/berry_blender.s b/asm/berry_blender.s
index 6d18ab7cb..fc7e747b9 100644
--- a/asm/berry_blender.s
+++ b/asm/berry_blender.s
@@ -516,7 +516,7 @@ _0807FBBE:
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _0807FC14
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _0807FC14
@@ -1122,7 +1122,7 @@ _08080126:
 	bne _0808016A
 	b _080804F8
 _0808016A:
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	bne _08080174
@@ -3334,7 +3334,7 @@ sub_80814B0: @ 80814B0
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _080814E4
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _080814E4
@@ -4706,7 +4706,7 @@ sub_8081F94: @ 8081F94
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08081FB8
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08081FB8
@@ -4852,7 +4852,7 @@ _080820EC:
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _0808218C
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _0808218C
@@ -4968,7 +4968,7 @@ _080821D4:
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08082254
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08082254
@@ -6250,7 +6250,7 @@ sub_8082D28: @ 8082D28
 	lsls r0, 24
 	lsrs r1, r0, 24
 _08082D3C:
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08082DCC
diff --git a/asm/cable_club.s b/asm/cable_club.s
index 15ba76e9c..254272c4d 100644
--- a/asm/cable_club.s
+++ b/asm/cable_club.s
@@ -2172,7 +2172,7 @@ sub_80B360C: @ 80B360C
 	movs r5, 0x1
 	eors r0, r5
 	bl sub_813C2A0
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _080B36B2
@@ -2512,7 +2512,7 @@ _080B391C:
 	thumb_func_start sub_80B3924
 sub_80B3924: @ 80B3924
 	push {lr}
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _080B3940
@@ -2552,7 +2552,7 @@ sub_80B3968: @ 80B3968
 	ldr r2, =0x00002211
 	adds r0, r2, 0
 	strh r0, [r1]
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _080B3994
@@ -2661,7 +2661,7 @@ _080B3A62:
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _080B3AA6
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	bne _080B3AA0
@@ -2752,7 +2752,7 @@ _080B3B20:
 	beq _080B3B9E
 	b _080B3BB8
 _080B3B2A:
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _080B3B40
@@ -2825,7 +2825,7 @@ _080B3BB8:
 	thumb_func_start sub_80B3BC4
 sub_80B3BC4: @ 80B3BC4
 	push {lr}
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	bne _080B3BD6
diff --git a/asm/contest_link_80FC4F4.s b/asm/contest_link_80FC4F4.s
index f1e2019da..953f69479 100644
--- a/asm/contest_link_80FC4F4.s
+++ b/asm/contest_link_80FC4F4.s
@@ -147,7 +147,7 @@ sub_80FC5DC: @ 80FC5DC
 	ldr r1, =gUnknown_02039F2A
 	movs r0, 0x1
 	strb r0, [r1]
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0x1
 	bne _080FC60C
diff --git a/asm/link.s b/asm/link.s
index 0f1c1cb68..5e5349f63 100644
--- a/asm/link.s
+++ b/asm/link.s
@@ -5,207 +5,10 @@
 
 	.text
 
-	thumb_func_start sub_800A44C
-sub_800A44C: @ 800A44C
-	ldr r0, =gUnknown_020223C0
-	ldr r0, [r0]
-	bx lr
-	.pool
-	thumb_func_end sub_800A44C
-
-	thumb_func_start sub_800A458
-sub_800A458: @ 800A458
-	push {lr}
-	ldr r0, =0x0000aaaa
-	bl sub_8009D90
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end sub_800A458
-
-	thumb_func_start GetMultiplayerId
-GetMultiplayerId: @ 800A468
-	push {lr}
-	ldr r0, =gLinkVSyncDisabled
-	ldrb r0, [r0]
-	cmp r0, 0x1
-	beq _0800A484
-	ldr r0, =0x04000128
-	ldr r0, [r0]
-	lsls r0, 26
-	lsrs r0, 30
-	b _0800A48C
-	.pool
-_0800A484:
-	bl rfu_get_multiplayer_id
-	lsls r0, 24
-	lsrs r0, 24
-_0800A48C:
-	pop {r1}
-	bx r1
-	thumb_func_end GetMultiplayerId
-
-	thumb_func_start bitmask_all_link_players_but_self
-bitmask_all_link_players_but_self: @ 800A490
-	push {lr}
-	bl GetMultiplayerId
-	adds r1, r0, 0
-	lsls r1, 24
-	lsrs r1, 24
-	movs r0, 0x1
-	lsls r0, r1
-	movs r1, 0xF
-	eors r0, r1
-	lsls r0, 24
-	lsrs r0, 24
-	pop {r1}
-	bx r1
-	thumb_func_end bitmask_all_link_players_but_self
-
-	thumb_func_start SendBlock
-SendBlock: @ 800A4AC
-	push {lr}
-	adds r3, r1, 0
-	lsls r2, 16
-	lsrs r1, r2, 16
-	ldr r0, =gLinkVSyncDisabled
-	ldrb r0, [r0]
-	cmp r0, 0x1
-	beq _0800A4C8
-	adds r0, r3, 0
-	bl sub_800A2F4
-	b _0800A4CE
-	.pool
-_0800A4C8:
-	adds r0, r3, 0
-	bl sub_800FE84
-_0800A4CE:
-	lsls r0, 24
-	lsrs r0, 24
-	pop {r1}
-	bx r1
-	thumb_func_end SendBlock
-
-	thumb_func_start sub_800A4D8
-sub_800A4D8: @ 800A4D8
-	push {lr}
-	lsls r0, 24
-	lsrs r1, r0, 24
-	adds r2, r1, 0
-	ldr r0, =gLinkVSyncDisabled
-	ldrb r0, [r0]
-	cmp r0, 0x1
-	bne _0800A4F8
-	adds r0, r1, 0
-	bl sub_8010100
-	lsls r0, 24
-	lsrs r0, 24
-	b _0800A514
-	.pool
-_0800A4F8:
-	ldr r0, =gUnknown_03003140
-	ldr r0, [r0]
-	cmp r0, 0
-	beq _0800A508
-	movs r0, 0
-	b _0800A514
-	.pool
-_0800A508:
-	ldr r0, =gUnknown_03003150
-	strb r2, [r0]
-	ldr r0, =0x0000cccc
-	bl sub_8009D90
-	movs r0, 0x1
-_0800A514:
-	pop {r1}
-	bx r1
-	.pool
-	thumb_func_end sub_800A4D8
-
-	thumb_func_start sub_800A520
-sub_800A520: @ 800A520
-	push {lr}
-	ldr r0, =gLinkVSyncDisabled
-	ldrb r0, [r0]
-	cmp r0, 0x1
-	bne _0800A538
-	bl sub_8010500
-	lsls r0, 24
-	lsrs r0, 24
-	b _0800A546
-	.pool
-_0800A538:
-	movs r1, 0
-	ldr r0, =gUnknown_03003140
-	ldr r0, [r0]
-	cmp r0, 0
-	bne _0800A544
-	movs r1, 0x1
-_0800A544:
-	adds r0, r1, 0
-_0800A546:
-	pop {r1}
-	bx r1
-	.pool
-	thumb_func_end sub_800A520
-
-	thumb_func_start GetBlockReceivedStatus
-GetBlockReceivedStatus: @ 800A550
-	push {lr}
-	ldr r0, =gLinkVSyncDisabled
-	ldrb r0, [r0]
-	cmp r0, 0x1
-	beq _0800A57C
-	ldr r2, =gUnknown_0300307C
-	ldrb r0, [r2, 0x3]
-	lsls r0, 3
-	ldrb r1, [r2, 0x2]
-	lsls r1, 2
-	orrs r0, r1
-	ldrb r1, [r2, 0x1]
-	lsls r1, 1
-	orrs r0, r1
-	ldrb r1, [r2]
-	orrs r0, r1
-	b _0800A580
-	.pool
-_0800A57C:
-	bl sub_800FCD8
-_0800A580:
-	lsls r0, 24
-	lsrs r0, 24
-	pop {r1}
-	bx r1
-	thumb_func_end GetBlockReceivedStatus
-
-	thumb_func_start sub_800A588
-sub_800A588: @ 800A588
-	push {lr}
-	lsls r0, 24
-	lsrs r1, r0, 24
-	ldr r0, =gLinkVSyncDisabled
-	ldrb r0, [r0]
-	cmp r0, 0x1
-	bne _0800A5A4
-	adds r0, r1, 0
-	bl sub_800F6FC
-	b _0800A5AC
-	.pool
-_0800A5A4:
-	ldr r0, =gUnknown_0300307C
-	adds r0, r1, r0
-	movs r1, 0x1
-	strb r1, [r0]
-_0800A5AC:
-	pop {r0}
-	bx r0
-	.pool
-	thumb_func_end sub_800A588
-
 	thumb_func_start ResetBlockReceivedFlags
 ResetBlockReceivedFlags: @ 800A5B4
 	push {r4,lr}
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0x1
 	bne _0800A5D4
@@ -240,7 +43,7 @@ ResetBlockReceivedFlag: @ 800A5EC
 	push {lr}
 	lsls r0, 24
 	lsrs r1, r0, 24
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0x1
 	bne _0800A608
@@ -986,7 +789,7 @@ sub_800ABAC: @ 800ABAC
 	thumb_func_start sub_800ABBC
 sub_800ABBC: @ 800ABBC
 	push {lr}
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	bne _0800ABDC
@@ -1019,7 +822,7 @@ sub_800ABF4: @ 800ABF4
 	push {lr}
 	lsls r0, 16
 	lsrs r3, r0, 16
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0x1
 	bne _0800AC0C
@@ -1046,7 +849,7 @@ _0800AC20:
 	thumb_func_start sub_800AC34
 sub_800AC34: @ 800AC34
 	push {lr}
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0x1
 	bne _0800AC48
@@ -1144,7 +947,7 @@ _0800ACF4:
 	thumb_func_start sub_800AD10
 sub_800AD10: @ 800AD10
 	push {lr}
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0x1
 	bne _0800AD24
@@ -1248,7 +1051,7 @@ _0800ADDA:
 	thumb_func_start sub_800ADF8
 sub_800ADF8: @ 800ADF8
 	push {lr}
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0x1
 	bne _0800AE0C
@@ -1415,7 +1218,7 @@ c2_800ACD4: @ 800AF30
 	bl FillPalette
 	bl ResetTasks
 	bl remove_some_task
-	ldr r1, =gLinkVSyncDisabled
+	ldr r1, =gSerialIsRFU
 	ldrb r0, [r1]
 	cmp r0, 0
 	beq _0800AF8C
@@ -1669,7 +1472,7 @@ _0800B20C:
 	bl PlaySE
 	b _0800B260
 _0800B214:
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0x2
 	bne _0800B244
@@ -1708,7 +1511,7 @@ _0800B260:
 	ldrb r1, [r1]
 	cmp r1, 0xA0
 	bne _0800B2D0
-	ldr r4, =gLinkVSyncDisabled
+	ldr r4, =gSerialIsRFU
 	ldrb r2, [r4]
 	cmp r2, 0x1
 	bne _0800B2A8
@@ -1910,7 +1713,7 @@ _0800B3F4:
 	thumb_func_start HandleLinkConnection
 HandleLinkConnection: @ 800B40C
 	push {r4,r5,lr}
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	bne _0800B45C
@@ -1965,7 +1768,7 @@ sub_800B488: @ 800B488
 	ldrb r0, [r0]
 	cmp r0, 0
 	bne _0800B498
-	ldr r1, =gLinkVSyncDisabled
+	ldr r1, =gSerialIsRFU
 	movs r0, 0x1
 	strb r0, [r1]
 _0800B498:
@@ -1981,7 +1784,7 @@ sub_800B4A4: @ 800B4A4
 	ldrb r1, [r0]
 	cmp r1, 0
 	bne _0800B4B2
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	strb r1, [r0]
 _0800B4B2:
 	pop {r0}
@@ -1996,7 +1799,7 @@ sub_800B4C0: @ 800B4C0
 	ldrb r1, [r0]
 	cmp r1, 0
 	bne _0800B4CE
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	strb r1, [r0]
 _0800B4CE:
 	pop {r0}
@@ -2007,7 +1810,7 @@ _0800B4CE:
 	thumb_func_start sub_800B4DC
 sub_800B4DC: @ 800B4DC
 	push {lr}
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	bne _0800B4FC
@@ -2041,7 +1844,7 @@ _0800B514:
 
 	thumb_func_start sub_800B518
 sub_800B518: @ 800B518
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	bx lr
 	.pool
diff --git a/asm/link_rfu.s b/asm/link_rfu.s
index d5d22a8db..a2b90dc7a 100644
--- a/asm/link_rfu.s
+++ b/asm/link_rfu.s
@@ -4737,7 +4737,7 @@ sub_800E3A8: @ 800E3A8
 	mov r5, r8
 	push {r5-r7}
 	sub sp, 0x20
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	bne _0800E3BE
@@ -9820,7 +9820,7 @@ sub_8010DB4: @ 8010DB4
 	cmp r0, 0
 	beq _08010DE4
 _08010DDE:
-	ldr r1, =gLinkVSyncDisabled
+	ldr r1, =gSerialIsRFU
 	movs r0, 0x2
 	strb r0, [r1]
 _08010DE4:
diff --git a/asm/record_mixing.s b/asm/record_mixing.s
index 7e9ea30d1..8a1f41126 100644
--- a/asm/record_mixing.s
+++ b/asm/record_mixing.s
@@ -621,7 +621,7 @@ _080E726C:
 	bne _080E730A
 	movs r0, 0x4
 	strh r0, [r5]
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	bne _080E7296
@@ -664,7 +664,7 @@ _080E72C0:
 	ldr r0, [r0]
 	bl Free
 	bl sub_808729C
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _080E72F8
@@ -2393,7 +2393,7 @@ _080E80C0:
 	lsls r0, 24
 	cmp r0, 0
 	bne _080E810A
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _080E80E8
diff --git a/asm/rom4.s b/asm/rom4.s
index fdb8d7a60..a7e98d013 100644
--- a/asm/rom4.s
+++ b/asm/rom4.s
@@ -3395,7 +3395,7 @@ c2_8056854: @ 8086140
 	ldr r0, =c1_link_related
 	bl set_callback1
 	bl sub_8086C2C
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08086174
@@ -3586,7 +3586,7 @@ sub_808631C: @ 808631C
 	bne _0808632E
 	bl sub_80097E8
 _0808632E:
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08086348
@@ -3768,7 +3768,7 @@ _080864DA:
 	bl cur_mapheader_run_tileset_funcs_after_some_cpuset
 	b _08086506
 _080864E0:
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08086506
@@ -4056,7 +4056,7 @@ _08086766:
 	bl cur_mapheader_run_tileset_funcs_after_some_cpuset
 	b _08086792
 _0808676C:
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08086792
@@ -4565,7 +4565,7 @@ _08086BCA:
 	thumb_func_start c1_link_related
 c1_link_related: @ 8086BD8
 	push {r4,lr}
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08086BF2
@@ -4631,7 +4631,7 @@ c1_link_related_func_set: @ 8086C50
 	thumb_func_start sub_8086C64
 sub_8086C64: @ 8086C64
 	push {lr}
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08086C82
@@ -5029,7 +5029,7 @@ _08086FC0:
 	movs r0, 0x11
 	strh r0, [r1]
 _08086FC6:
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08086FFC
@@ -5926,7 +5926,7 @@ _08087666:
 	thumb_func_start sub_808766C
 sub_808766C: @ 808766C
 	push {lr}
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	bne _08087688
@@ -5946,7 +5946,7 @@ _0808768A:
 	thumb_func_start sub_8087690
 sub_8087690: @ 8087690
 	push {lr}
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	bne _080876B0
diff --git a/asm/rom6.s b/asm/rom6.s
index 87b780ba5..20058db9d 100644
--- a/asm/rom6.s
+++ b/asm/rom6.s
@@ -11823,7 +11823,7 @@ _0813B790:
 	b _0813B7C6
 	.pool
 _0813B7A8:
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	bne _0813B7B4
diff --git a/asm/rom_8011DC0.s b/asm/rom_8011DC0.s
index 8185238bd..fc70f498a 100644
--- a/asm/rom_8011DC0.s
+++ b/asm/rom_8011DC0.s
@@ -28592,7 +28592,7 @@ sub_8020C70: @ 8020C70
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08020C8E
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	bne _08020CAC
diff --git a/asm/start_menu.s b/asm/start_menu.s
index 3c8c4c3cf..0da38ba4b 100644
--- a/asm/start_menu.s
+++ b/asm/start_menu.s
@@ -1712,7 +1712,7 @@ _080A05AC:
 	movs r2, 0x10
 	movs r3, 0
 	bl BeginNormalPaletteFade
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _080A0620
diff --git a/asm/trade.s b/asm/trade.s
index ebb624d90..61a814421 100644
--- a/asm/trade.s
+++ b/asm/trade.s
@@ -135,7 +135,7 @@ _08077258:
 	thumb_func_start sub_8077260
 sub_8077260: @ 8077260
 	push {lr}
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08077280
@@ -409,7 +409,7 @@ _080774B2:
 	ldr r0, [r0]
 	adds r0, 0xA8
 	strb r2, [r0]
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08077528
@@ -531,7 +531,7 @@ _08077600:
 	ldr r0, [r0]
 	adds r0, 0xA8
 	strb r2, [r0]
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	bne _0807762A
@@ -543,7 +543,7 @@ _0807762A:
 	b _08077B46
 	.pool
 _08077648:
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08077680
@@ -1182,7 +1182,7 @@ _08077C28:
 	b _080780D8
 	.pool
 _08077C3C:
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08077C50
@@ -1780,7 +1780,7 @@ sub_807816C: @ 807816C
 	adds r0, 0x7E
 	ldrb r0, [r0]
 	strb r0, [r1, 0x1]
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _080781B4
@@ -1809,7 +1809,7 @@ sub_80781C8: @ 80781C8
 	ldr r5, =gMain
 	ldr r0, =sub_80773AC
 	str r0, [r5, 0x8]
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08078220
@@ -4004,7 +4004,7 @@ sub_8079490: @ 8079490
 	ands r0, r1
 	cmp r0, 0
 	bne _080794C4
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _080794B4
@@ -4029,7 +4029,7 @@ _080794C4:
 	thumb_func_start sub_80794CC
 sub_80794CC: @ 80794CC
 	push {lr}
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _08079518
@@ -7507,7 +7507,7 @@ _0807B0F0:
 	ands r0, r1
 	cmp r0, 0
 	bne _0807B116
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _0807B110
@@ -13831,7 +13831,7 @@ _0807EDC0:
 	movs r0, 0x15
 	bl IncrementGameStat
 _0807EDCE:
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _0807EDF6
@@ -14044,7 +14044,7 @@ _0807EFA4:
 	lsrs r0, 24
 	cmp r0, 0x1
 	bne _0807F03A
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _0807EFD8
@@ -14071,7 +14071,7 @@ _0807EFE4:
 	b _0807F03A
 	.pool
 _0807EFF0:
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _0807F028
@@ -14141,7 +14141,7 @@ c2_080543C4: @ 807F068
 	ldr r0, [r4]
 	bl Free
 	str r5, [r4]
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0
 	beq _0807F0B6
diff --git a/asm/trainer_card.s b/asm/trainer_card.s
index bee1f4f7f..4f1183477 100644
--- a/asm/trainer_card.s
+++ b/asm/trainer_card.s
@@ -187,7 +187,7 @@ _080C2830:
 	bl sub_80C4630
 	b _080C28D4
 _080C2836:
-	ldr r0, =gLinkVSyncDisabled
+	ldr r0, =gSerialIsRFU
 	ldrb r0, [r0]
 	cmp r0, 0x1
 	bne _080C2852
diff --git a/include/link.h b/include/link.h
index 9c9793249..8ec0431aa 100644
--- a/include/link.h
+++ b/include/link.h
@@ -29,6 +29,8 @@
 #define MASTER_HANDSHAKE 0x8FFF
 #define SLAVE_HANDSHAKE  0xB9A0
 
+#define SIO_MULTI_CNT ((volatile struct SioMultiCnt *)REG_ADDR_SIOCNT)
+
 enum
 {
     LINK_STATE_START0,
@@ -142,7 +144,7 @@ extern u8 gShouldAdvanceLinkState;
 extern struct LinkPlayer gLinkPlayers[];
 extern u16 word_3002910[];
 extern bool8 gReceivedRemoteLinkPlayers;
-extern bool8 gLinkVSyncDisabled;
+extern bool8 gSerialIsRFU;
 
 void Task_DestroySelf(u8);
 void OpenLink(void);
@@ -162,7 +164,7 @@ void sub_8007E24(void);
 void sub_8007E4C(void);
 u8 GetMultiplayerId(void);
 u8 bitmask_all_link_players_but_self(void);
-bool8 SendBlock(u8, void *, u16);
+bool8 SendBlock(u8, const void *, u16);
 u8 GetBlockReceivedStatus(void);
 void ResetBlockReceivedFlags(void);
 void ResetBlockReceivedFlag(u8);
@@ -183,7 +185,6 @@ u8 GetLinkPlayerCount(void);
 
 void sub_800E0E8(void);
 bool8 sub_800A520(void);
-bool8 sub_8010500(void);
 void sub_800DFB4(u8, u8);
 void sub_800ADF8(void);
 void sub_800B488(void);
@@ -215,7 +216,7 @@ extern u8 gUnknown_030030EC[4];
 extern u8 gUnknown_030030F0[4];
 extern u16 gUnknown_030030F4;
 extern u8 gUnknown_030030F8;
-extern bool8 gLinkVSyncDisabled;
+extern bool8 gSerialIsRFU;
 extern bool8 gUnknown_03003100;
 extern u16 gUnknown_03003110[8];
 extern u8 gUnknown_03003120;
diff --git a/include/link_rfu.h b/include/link_rfu.h
new file mode 100644
index 000000000..ff71c65aa
--- /dev/null
+++ b/include/link_rfu.h
@@ -0,0 +1,24 @@
+#ifndef GUARD_LINK_RFU_H
+#define GUARD_LINK_RFU_H
+
+// Exported type declarations
+
+// Exported RAM declarations
+
+// Exported ROM declarations
+u32 sub_800BEC0(void);
+void sub_800E700(void);
+void sub_800EDD4(void);
+bool32 sub_800F7E4(void);
+void sub_800F804(void);
+void sub_800F850(void);
+void Rfu_set_zero(void);
+u8 sub_80104F4(void);
+u8 rfu_get_multiplayer_id(void);
+bool32 sub_800FE84(const void *src, size_t size);
+bool8 sub_8010100(u8 a0);
+bool8 sub_8010500(void);
+u8 sub_800FCD8(void);
+void sub_800F6FC(u8 who);
+
+#endif //GUARD_LINK_RFU_H
diff --git a/src/battle_2.c b/src/battle_2.c
index 24b43bdbd..a69a16dac 100644
--- a/src/battle_2.c
+++ b/src/battle_2.c
@@ -17,6 +17,7 @@
 #include "items.h"
 #include "hold_effects.h"
 #include "link.h"
+#include "link_rfu.h"
 #include "bg.h"
 #include "dma3.h"
 #include "string_util.h"
@@ -734,7 +735,7 @@ static void CB2_HandleStartBattle(void)
             sub_805EF14();
             gBattleCommunication[MULTIUSE_STATE] = 1;
         }
-        if (gLinkVSyncDisabled)
+        if (gSerialIsRFU)
             sub_800E0E8();
         break;
     case 1:
@@ -758,7 +759,7 @@ static void CB2_HandleStartBattle(void)
                     SendBlock(bitmask_all_link_players_but_self(), &gBattleStruct->field_180, 32);
                     gBattleCommunication[MULTIUSE_STATE] = 2;
                 }
-                if (gLinkVSyncDisabled)
+                if (gSerialIsRFU)
                     sub_800DFB4(0, 0);
             }
         }
@@ -929,7 +930,7 @@ static void CB2_HandleStartMultiPartnerBattle(void)
             sub_805EF14();
             gBattleCommunication[MULTIUSE_STATE] = 1;
         }
-        if (gLinkVSyncDisabled)
+        if (gSerialIsRFU)
             sub_800E0E8();
         // fall through
     case 1:
@@ -960,7 +961,7 @@ static void CB2_HandleStartMultiPartnerBattle(void)
                     gBattleCommunication[MULTIUSE_STATE] = 2;
                 }
 
-                if (gLinkVSyncDisabled)
+                if (gSerialIsRFU)
                     sub_800DFB4(0, 0);
             }
         }
@@ -1237,14 +1238,14 @@ static void CB2_PreInitMultiBattle(void)
         if (sub_800A520() && !gPaletteFade.active)
         {
             gBattleCommunication[MULTIUSE_STATE]++;
-            if (gLinkVSyncDisabled)
+            if (gSerialIsRFU)
                 sub_800ADF8();
             else
                 sub_800AC34();
         }
         break;
     case 3:
-        if (gLinkVSyncDisabled)
+        if (gSerialIsRFU)
         {
             if (sub_8010500())
             {
@@ -1329,7 +1330,7 @@ static void CB2_HandleStartMultiBattle(void)
             sub_805EF14();
             gBattleCommunication[MULTIUSE_STATE] = 1;
         }
-        if (gLinkVSyncDisabled)
+        if (gSerialIsRFU)
             sub_800E0E8();
         break;
     case 1:
@@ -1347,7 +1348,7 @@ static void CB2_HandleStartMultiBattle(void)
                     SendBlock(bitmask_all_link_players_but_self(), &gBattleStruct->field_180, 32);
                     gBattleCommunication[MULTIUSE_STATE]++;
                 }
-                if (gLinkVSyncDisabled)
+                if (gSerialIsRFU)
                     sub_800DFB4(0, 0);
             }
         }
@@ -2132,12 +2133,12 @@ static void sub_8038F34(void)
         }
         break;
     case 8:
-        if (!gLinkVSyncDisabled)
+        if (!gSerialIsRFU)
             sub_800AC34();
         gBattleCommunication[MULTIUSE_STATE]++;
         break;
     case 9:
-        if (!gMain.field_439_x4 || gLinkVSyncDisabled || gReceivedRemoteLinkPlayers != 1)
+        if (!gMain.field_439_x4 || gSerialIsRFU || gReceivedRemoteLinkPlayers != 1)
         {
             gMain.field_439_x4 = 0;
             SetMainCallback2(gMain.savedCallback);
@@ -2316,13 +2317,13 @@ static void sub_803939C(void)
     case 8:
         if (--gBattleCommunication[1] == 0)
         {
-            if (gMain.field_439_x4 && !gLinkVSyncDisabled)
+            if (gMain.field_439_x4 && !gSerialIsRFU)
                 sub_800AC34();
             gBattleCommunication[MULTIUSE_STATE]++;
         }
         break;
     case 9:
-        if (!gMain.field_439_x4 || gLinkVSyncDisabled || gReceivedRemoteLinkPlayers != 1)
+        if (!gMain.field_439_x4 || gSerialIsRFU || gReceivedRemoteLinkPlayers != 1)
         {
             gMain.field_439_x4 = 0;
             if (!gPaletteFade.active)
diff --git a/src/battle_controller_player.c b/src/battle_controller_player.c
index 10d361cb9..2a882de99 100644
--- a/src/battle_controller_player.c
+++ b/src/battle_controller_player.c
@@ -896,7 +896,7 @@ static void HandleMoveSwitchting(void)
 
 static void sub_80586F8(void)
 {
-    if (gLinkVSyncDisabled == 0)
+    if (gSerialIsRFU == 0)
     {
         if (gReceivedRemoteLinkPlayers == 0)
         {
@@ -932,7 +932,7 @@ void sub_80587B0(void)
         {
             if (sub_800A520())
             {
-                if (gLinkVSyncDisabled == 0)
+                if (gSerialIsRFU == 0)
                     sub_800AC34();
                 else
                     sub_800ADF8();
diff --git a/src/battle_controllers.c b/src/battle_controllers.c
index d3653d0b3..d741a8a98 100644
--- a/src/battle_controllers.c
+++ b/src/battle_controllers.c
@@ -59,7 +59,7 @@ void HandleLinkBattleSetup(void)
 {
     if (gBattleTypeFlags & BATTLE_TYPE_LINK)
     {
-        if (gLinkVSyncDisabled)
+        if (gSerialIsRFU)
             sub_800B488();
         if (!gReceivedRemoteLinkPlayers)
             sub_8009734();
@@ -780,7 +780,7 @@ static void Task_HandleSendLinkBuffersData(u8 taskId)
             gTasks[taskId].data[11]++;
         break;
     case 2:
-        if (gLinkVSyncDisabled)
+        if (gSerialIsRFU)
         {
             gTasks[taskId].data[11]++;
         }
diff --git a/src/evolution_scene.c b/src/evolution_scene.c
index 68731a14a..101feab56 100644
--- a/src/evolution_scene.c
+++ b/src/evolution_scene.c
@@ -405,7 +405,7 @@ static void CB2_TradeEvolutionSceneLoadGraphics(void)
         }
         break;
     case 6:
-        if (gLinkVSyncDisabled)
+        if (gSerialIsRFU)
         {
             sub_800E0E8();
             sub_800DFB4(0, 0);
@@ -1188,7 +1188,7 @@ static void Task_TradeEvolutionScene(u8 taskID)
         case 5:
             if (!gPaletteFade.active)
             {
-                if (gLinkVSyncDisabled)
+                if (gSerialIsRFU)
                     sub_800E084();
 
                 Free(GetBgTilemapBuffer(3));
diff --git a/src/link.c b/src/link.c
index d9d5a48dd..68868491b 100644
--- a/src/link.c
+++ b/src/link.c
@@ -16,6 +16,7 @@
 #include "palette.h"
 #include "task.h"
 #include "trade.h"
+#include "link_rfu.h"
 #include "link.h"
 
 // Static type declarations
@@ -37,13 +38,6 @@ struct LinkTestBGInfo
     u32 dummy_C;
 };
 
-struct SIOCnt {
-    u32 cnt0_0:4;
-    u32 cnt0_2:2;
-};
-
-#define REG_SIOCNT_STRUCT (*(volatile struct SIOCnt *)REG_ADDR_SIOCNT)
-
 // Static RAM declarations
 
 IWRAM_DATA struct BlockTransfer gUnknown_03000D10;
@@ -88,7 +82,7 @@ u8 gUnknown_030030EC[MAX_LINK_PLAYERS];
 u8 gUnknown_030030F0[MAX_LINK_PLAYERS];
 u16 gUnknown_030030F4;
 u8 gUnknown_030030F8;
-bool8 gLinkVSyncDisabled;
+bool8 gSerialIsRFU;
 bool8 gUnknown_03003100;
 u16 gUnknown_03003110[8];
 u8 gUnknown_03003120;
@@ -137,16 +131,6 @@ void sub_800B524(struct LinkPlayer *linkPlayer);
 void sub_800B53C(void);
 void sub_800B594(void);
 
-// rfu
-u32 sub_800BEC0(void);
-void sub_800E700(void);
-void sub_800EDD4(void);
-bool32 sub_800F7E4(void);
-void sub_800F804(void);
-void sub_800F850(void);
-void Rfu_set_zero(void);
-u8 sub_80104F4(void);
-
 // .rodata
 
 ALIGNED(4) const u16 gWirelessLinkDisplayPal[] = INCBIN_U16("graphics/interface/wireless_link_display.gbapal");
@@ -333,7 +317,7 @@ void sub_8009734(void)
 {
     int i;
 
-    if (!gLinkVSyncDisabled)
+    if (!gSerialIsRFU)
     {
         sub_800B628();
         sub_80096D0();
@@ -365,7 +349,7 @@ void sub_8009734(void)
 void sub_80097E8(void)
 {
     gReceivedRemoteLinkPlayers = FALSE;
-    if (gLinkVSyncDisabled)
+    if (gSerialIsRFU)
     {
         sub_800EDD4();
     }
@@ -467,7 +451,7 @@ u16 sub_80099E0(const u16 *src)
     gUnknown_03003084 = *src;
     if (gUnknown_030030E0 & 0x40)
     {
-        sub_8009AA0(REG_SIOCNT_STRUCT.cnt0_2);
+        sub_8009AA0(SIO_MULTI_CNT->id);
         if (gUnknown_03003140 != NULL)
         {
             gUnknown_03003140();
@@ -685,7 +669,7 @@ void sub_8009D90(u16 command)
 
 void sub_8009F18(void)
 {
-    if (gLinkVSyncDisabled)
+    if (gSerialIsRFU)
     {
         sub_800F804();
     }
@@ -694,7 +678,7 @@ void sub_8009F18(void)
 
 bool32 sub_8009F3C(void)
 {
-    if (gLinkVSyncDisabled)
+    if (gSerialIsRFU)
     {
         return sub_800F7E4();
     }
@@ -715,7 +699,7 @@ static void sub_8009F70(void)
 
 void sub_8009F8C(void)
 {
-    if (gLinkVSyncDisabled)
+    if (gSerialIsRFU)
     {
         Rfu_set_zero();
     }
@@ -727,7 +711,7 @@ void sub_8009F8C(void)
 
 void sub_8009FAC(void)
 {
-    if (gLinkVSyncDisabled)
+    if (gSerialIsRFU)
     {
         Rfu_set_zero();
     }
@@ -739,7 +723,7 @@ void sub_8009FAC(void)
 
 u8 GetLinkPlayerCount(void)
 {
-    if (gLinkVSyncDisabled)
+    if (gSerialIsRFU)
     {
         return sub_80104F4();
     }
@@ -997,7 +981,7 @@ void sub_800A3F8(void)
 void sub_800A418(void)
 {
     gUnknown_020223C0 = 0;
-    if (gLinkVSyncDisabled)
+    if (gSerialIsRFU)
     {
         sub_800F850();
     }
@@ -1006,3 +990,84 @@ void sub_800A418(void)
         gUnknown_03003140 = sub_800A3F8;
     }
 }
+
+u32 sub_800A44C(void)
+{
+    return gUnknown_020223C0;
+}
+
+void sub_800A458(void)
+{
+    sub_8009D90(0xaaaa);
+}
+
+u8 GetMultiplayerId(void)
+{
+    if (gSerialIsRFU == TRUE)
+    {
+        return rfu_get_multiplayer_id();
+    }
+    return SIO_MULTI_CNT->id;
+}
+
+u8 bitmask_all_link_players_but_self(void)
+{
+    u8 mpId;
+
+    mpId = GetMultiplayerId();
+    return ((1 << MAX_LINK_PLAYERS) - 1) ^ (1 << mpId);
+}
+
+bool8 SendBlock(u8 unused, const void *src, u16 size)
+{
+    if (gSerialIsRFU == TRUE)
+    {
+        return sub_800FE84(src, size);
+    }
+    return sub_800A2F4(src, size);
+}
+
+bool8 sub_800A4D8(u8 a0)
+{
+    if (gSerialIsRFU == TRUE)
+    {
+        return sub_8010100(a0);
+    }
+    if (gUnknown_03003140 == NULL)
+    {
+        gUnknown_03003150 = a0;
+        sub_8009D90(0xcccc);
+        return TRUE;
+    }
+    return FALSE;
+}
+
+bool8 sub_800A520(void)
+{
+    if (gSerialIsRFU == TRUE)
+    {
+        return sub_8010500();
+    }
+    return gUnknown_03003140 == NULL;
+}
+
+u8 GetBlockReceivedStatus(void)
+{
+    if (gSerialIsRFU == TRUE)
+    {
+        return sub_800FCD8();
+    }
+    return (gUnknown_0300307C[3] << 3) | (gUnknown_0300307C[2] << 2) | (gUnknown_0300307C[1] << 1) | (gUnknown_0300307C[0] << 0);
+}
+
+void sub_800A588(u8 who)
+{
+    if (gSerialIsRFU == TRUE)
+    {
+        sub_800F6FC(who);
+    }
+    else
+    {
+        gUnknown_0300307C[who] = TRUE;
+    }
+}
diff --git a/src/main.c b/src/main.c
index b90dc3837..61f6f60a4 100644
--- a/src/main.c
+++ b/src/main.c
@@ -336,7 +336,7 @@ extern void ProcessDma3Requests(void);
 
 static void VBlankIntr(void)
 {
-    if (gLinkVSyncDisabled != FALSE)
+    if (gSerialIsRFU != FALSE)
         LinkVSync();
     else if (gUnknown_03002748 == FALSE)
         sub_800B9B8();
diff --git a/src/reshow_battle_screen.c b/src/reshow_battle_screen.c
index 002f4f069..87ad20ed7 100644
--- a/src/reshow_battle_screen.c
+++ b/src/reshow_battle_screen.c
@@ -177,7 +177,7 @@ static void CB2_ReshowBattleScreenAfterMenu(void)
 
             ActionSelectionCreateCursorAt(gActionSelectionCursor[gBankInMenu], 0);
 
-            if (gLinkVSyncDisabled != 0 && gReceivedRemoteLinkPlayers != 0)
+            if (gSerialIsRFU != 0 && gReceivedRemoteLinkPlayers != 0)
             {
                 sub_800E0E8();
                 sub_800DFB4(0, 0);
diff --git a/sym_common.txt b/sym_common.txt
index 7a35ae5bd..e228ed613 100644
--- a/sym_common.txt
+++ b/sym_common.txt
@@ -60,7 +60,7 @@ gUnknown_030030F4: @ 30030F4
 gUnknown_030030F8: @ 30030F8
 	.space 0x4
 
-gLinkVSyncDisabled: @ 30030FC
+gSerialIsRFU: @ 30030FC
 	.space 0x4
 
 gUnknown_03003100: @ 3003100