diff --git a/data/maps/LittlerootTown_ProfessorBirchsLab/scripts.inc b/data/maps/LittlerootTown_ProfessorBirchsLab/scripts.inc
index 4ebc03c8c..b9ce0c809 100644
--- a/data/maps/LittlerootTown_ProfessorBirchsLab/scripts.inc
+++ b/data/maps/LittlerootTown_ProfessorBirchsLab/scripts.inc
@@ -584,7 +584,7 @@ LittlerootTown_ProfessorBirchsLab_EventScript_ReceivePokedex:: @ 81FA3AC
 	message LittlerootTown_ProfessorBirchsLab_Text_ReceivedPokedex
 	waitfanfare
 	setflag FLAG_SYS_POKEDEX_GET
-	special sub_81AFDA0  @ sets flags that are never read
+	special SetUnlockedPokedexFlags
 	setflag FLAG_RECEIVED_POKEDEX_FROM_BIRCH
 	setvar VAR_CABLE_CLUB_TUTORIAL_STATE, 1
 	return
diff --git a/data/specials.inc b/data/specials.inc
index fb2e8fe75..97cc3c782 100644
--- a/data/specials.inc
+++ b/data/specials.inc
@@ -504,7 +504,7 @@ gSpecials:: @ 81DBA64
 	def_special GetMartEmployeeObjectEventId
 	def_special sub_80A08CC
 	def_special Unused_SetWeatherSunny
-	def_special sub_81AFDA0
+	def_special SetUnlockedPokedexFlags
 	def_special IsTrainerRegistered
 	def_special ShouldDoBrailleRegicePuzzle
 	def_special EnableNationalPokedex
diff --git a/include/global.h b/include/global.h
index e3c8fee55..bcf3e6486 100644
--- a/include/global.h
+++ b/include/global.h
@@ -465,7 +465,7 @@ struct SaveBlock2
     /*0x90*/ u8 filler_90[0x8];
     /*0x98*/ struct Time localTimeOffset;
     /*0xA0*/ struct Time lastBerryTreeUpdate;
-    /*0xA8*/ u32 field_A8; // Written to, but never read.
+    /*0xA8*/ u32 gcnLinkFlags; // Read by Pokemon Colosseum/XD
     /*0xAC*/ u32 encryptionKey;
     /*0xB0*/ struct PlayersApprentice playerApprentice;
     /*0xDC*/ struct Apprentice apprentices[APPRENTICE_COUNT];
diff --git a/include/save_location.h b/include/save_location.h
index 6c2ae0e6b..53f317c57 100644
--- a/include/save_location.h
+++ b/include/save_location.h
@@ -13,7 +13,6 @@
 #define CHAMPION_SAVEWARP            (1 << 7)
 
 void TrySetMapSaveWarpStatus(void);
-void sub_81AFDA0(void);
 void SetChampionSaveWarp(void);
 
 #endif // GUARD_SAVE_LOCATION_H
diff --git a/src/new_game.c b/src/new_game.c
index 464da6414..290c0c2bb 100644
--- a/src/new_game.c
+++ b/src/new_game.c
@@ -162,7 +162,7 @@ void NewGameInitData(void)
     ClearSav1();
     ClearMailData();
     gSaveBlock2Ptr->specialSaveWarpFlags = 0;
-    gSaveBlock2Ptr->field_A8 = 0;
+    gSaveBlock2Ptr->gcnLinkFlags = 0;
     InitPlayerTrainerId();
     PlayTimeCounter_Reset();
     ClearPokedexFlags();
diff --git a/src/save_location.c b/src/save_location.c
index 6bf5eceb0..aa56d7b16 100644
--- a/src/save_location.c
+++ b/src/save_location.c
@@ -118,17 +118,18 @@ void TrySetMapSaveWarpStatus(void)
     sub_81AFD5C();
 }
 
-// Called when receiving the Pokedex
-// Only place field_A8 is written (aside from clearing on new game), never read
-void sub_81AFDA0(void)
+// In FRLG, only 0x1, 0x10, and 0x20 are set when the pokedex is received
+// 0x2, 0x4, 0x8, and 0x8000 are instead set by SetPostgameFlags
+// These flags are read by Pokemon Colosseum/XD for linking. XD Additionally requires FLAG_SYS_GAME_CLEAR
+void SetUnlockedPokedexFlags(void)
 {
-    gSaveBlock2Ptr->field_A8 |= 0x8000;
-    gSaveBlock2Ptr->field_A8 |= 0x1;
-    gSaveBlock2Ptr->field_A8 |= 0x2;
-    gSaveBlock2Ptr->field_A8 |= 0x4;
-    gSaveBlock2Ptr->field_A8 |= 0x10;
-    gSaveBlock2Ptr->field_A8 |= 0x20;
-    gSaveBlock2Ptr->field_A8 |= 0x8;
+    gSaveBlock2Ptr->gcnLinkFlags |= 0x8000;
+    gSaveBlock2Ptr->gcnLinkFlags |= 0x1;
+    gSaveBlock2Ptr->gcnLinkFlags |= 0x2;
+    gSaveBlock2Ptr->gcnLinkFlags |= 0x4;
+    gSaveBlock2Ptr->gcnLinkFlags |= 0x10;
+    gSaveBlock2Ptr->gcnLinkFlags |= 0x20;
+    gSaveBlock2Ptr->gcnLinkFlags |= 0x8;
 }
 
 void SetChampionSaveWarp(void)