diff --git a/include/config/battle.h b/include/config/battle.h
index fd390debf0ec..7e0f05a81947 100644
--- a/include/config/battle.h
+++ b/include/config/battle.h
@@ -46,6 +46,7 @@
 #define B_PRANKSTER_DARK_TYPES      GEN_LATEST // In Gen7+, Prankster-elevated status moves do not affect Dark type Pokémon.
 #define B_SHEER_COLD_IMMUNITY       GEN_LATEST // In Gen7+, Ice-types are immune to Sheer Cold
 #define B_ROOST_PURE_FLYING         GEN_LATEST // In Gen5+, Roost makes pure Flying-types into Normal-type.
+#define B_STATUS_TYPE_IMMUNITY      GEN_LATEST // In Gen1, Pokémon were immune to paralysis/freeze/burn side effects of attacking moves, if they shared a type with the move.
 
 // Turn settings
 #define B_BINDING_TURNS             GEN_LATEST // In Gen5+, binding moves last for 4-5 turns instead of 2-5 turns. (With Grip Claw, 7 and 5 turns respectively.)
diff --git a/include/item_use.h b/include/item_use.h
index e9a2bad34906..fe801083adab 100644
--- a/include/item_use.h
+++ b/include/item_use.h
@@ -54,5 +54,6 @@ enum {
 };
 
 bool32 CanThrowBall(void);
+bool32 CannotUseItemsInBattle(u16 itemId, struct Pokemon *mon);
 
 #endif // GUARD_ITEM_USE_H
diff --git a/src/battle_script_commands.c b/src/battle_script_commands.c
index 34a3da0857d2..0272aa4108db 100644
--- a/src/battle_script_commands.c
+++ b/src/battle_script_commands.c
@@ -2933,12 +2933,27 @@ void SetMoveEffect(bool32 primary, u32 certain)
                 RESET_RETURN
             }
 
+            if (B_STATUS_TYPE_IMMUNITY == GEN_1)
+            {
+                u8 moveType = 0;
+                GET_MOVE_TYPE(gCurrentMove, moveType);
+                if (primary == FALSE && certain != MOVE_EFFECT_CERTAIN && IS_BATTLER_OF_TYPE(gEffectBattler, moveType))
+                    break;
+            }
+
             if (!CanBeBurned(gEffectBattler))
                 break;
 
             statusChanged = TRUE;
             break;
         case STATUS1_FREEZE:
+            if (B_STATUS_TYPE_IMMUNITY == GEN_1)
+            {
+                u8 moveType = 0;
+                GET_MOVE_TYPE(gCurrentMove, moveType);
+                if (primary == FALSE && certain != MOVE_EFFECT_CERTAIN && IS_BATTLER_OF_TYPE(gEffectBattler, moveType))
+                    break;
+            }
             if (!CanBeFrozen(gEffectBattler))
                 break;
 
@@ -2972,6 +2987,13 @@ void SetMoveEffect(bool32 primary, u32 certain)
                 else
                     break;
             }
+            if (B_STATUS_TYPE_IMMUNITY == GEN_1)
+            {
+                u8 moveType = 0;
+                GET_MOVE_TYPE(gCurrentMove, moveType);
+                if (primary == FALSE && certain != MOVE_EFFECT_CERTAIN && IS_BATTLER_OF_TYPE(gEffectBattler, moveType))
+                    break;
+            }
             if (!CanParalyzeType(gBattleScripting.battler, gEffectBattler)
                 && (gHitMarker & HITMARKER_STATUS_ABILITY_EFFECT)
                 && (primary == TRUE || certain == MOVE_EFFECT_CERTAIN))
@@ -3036,6 +3058,13 @@ void SetMoveEffect(bool32 primary, u32 certain)
             }
             break;
         case STATUS1_FROSTBITE:
+            if (B_STATUS_TYPE_IMMUNITY == GEN_1)
+            {
+                u8 moveType = 0;
+                GET_MOVE_TYPE(gCurrentMove, moveType);
+                if (primary == FALSE && certain != MOVE_EFFECT_CERTAIN && IS_BATTLER_OF_TYPE(gEffectBattler, moveType))
+                    break;
+            }
             if (!CanGetFrostbite(gEffectBattler))
                 break;
 
diff --git a/src/battle_tower.c b/src/battle_tower.c
index 015f6d207f34..6dba9a63eda4 100644
--- a/src/battle_tower.c
+++ b/src/battle_tower.c
@@ -2989,6 +2989,8 @@ static void FillPartnerParty(u16 trainerId)
                 otID = STEVEN_OTID;
             else
                 otID = ((firstIdPart % 72) * 1000) + ((secondIdPart % 23) * 10) + (thirdIdPart % 37) % 65536;
+
+            do
             {
                 personality = Random32();
             } while (IsShinyOtIdPersonality(otID, personality));
diff --git a/src/item_use.c b/src/item_use.c
index 53da18ee9855..be253a10a855 100644
--- a/src/item_use.c
+++ b/src/item_use.c
@@ -78,7 +78,6 @@ static void SetDistanceOfClosestHiddenItem(u8, s16, s16);
 static void CB2_OpenPokeblockFromBag(void);
 static void ItemUseOnFieldCB_Honey(u8 taskId);
 static bool32 IsValidLocationForVsSeeker(void);
-static bool32 CannotUseBagBattleItem(u16 itemId);
 
 // EWRAM variables
 EWRAM_DATA static void(*sItemUseOnFieldCB)(u8 taskId) = NULL;
@@ -1142,11 +1141,13 @@ void ItemUseInBattle_PartyMenuChooseMove(u8 taskId)
 }
 
 // Returns whether an item can be used in battle and sets the fail text.
-static bool32 CannotUseBagBattleItem(u16 itemId)
+bool32 CannotUseItemsInBattle(u16 itemId, struct Pokemon *mon)
 {
-    u8 cannotUse = FALSE;
     u16 battleUsage = ItemId_GetBattleUsage(itemId);
+    bool8 cannotUse = FALSE;
     const u8* failStr = NULL;
+    u32 i;
+    u16 hp = GetMonData(mon, MON_DATA_HP);
 
     // Embargo Check
     if ((gPartyMenu.slotId == 0 && gStatuses3[B_POSITION_PLAYER_LEFT] & STATUS3_EMBARGO)
@@ -1154,77 +1155,105 @@ static bool32 CannotUseBagBattleItem(u16 itemId)
     {
         return TRUE;
     }
-    // X-Items
-    if (battleUsage == EFFECT_ITEM_INCREASE_STAT
-        && gBattleMons[gBattlerInMenuId].statStages[gItemEffectTable[itemId][1]] == MAX_STAT_STAGE)
-    {
-        cannotUse++;
-    }
-    // Dire Hit
-    if (battleUsage == EFFECT_ITEM_SET_FOCUS_ENERGY
-        && (gBattleMons[gBattlerInMenuId].status2 & STATUS2_FOCUS_ENERGY))
-    {
-        cannotUse++;
-    }
-    // Guard Spec
-    if (battleUsage == EFFECT_ITEM_SET_MIST
-        && gSideStatuses[GetBattlerSide(gBattlerInMenuId)] & SIDE_STATUS_MIST)
-    {
-        cannotUse++;
-    }
-    // Escape Items
-    if (battleUsage == EFFECT_ITEM_ESCAPE
-        && gBattleTypeFlags & BATTLE_TYPE_TRAINER)
-    {
-        cannotUse++;
-    }
-    // Poke Balls
-    if (battleUsage == EFFECT_ITEM_THROW_BALL)
+
+    // battleUsage checks
+    switch (battleUsage)
     {
+    case EFFECT_ITEM_INCREASE_STAT:
+        if (gBattleMons[gBattlerInMenuId].statStages[gItemEffectTable[itemId][1]] == MAX_STAT_STAGE)
+            cannotUse = TRUE;
+        break;
+    case EFFECT_ITEM_SET_FOCUS_ENERGY:
+        if (gBattleMons[gBattlerInMenuId].status2 & STATUS2_FOCUS_ENERGY)
+            cannotUse = TRUE;
+        break;
+    case EFFECT_ITEM_SET_MIST:
+        if (gSideStatuses[GetBattlerSide(gBattlerInMenuId)] & SIDE_STATUS_MIST)
+            cannotUse = TRUE;
+        break;
+    case EFFECT_ITEM_ESCAPE:
+        if (gBattleTypeFlags & BATTLE_TYPE_TRAINER)
+            cannotUse = TRUE;
+        break;
+    case EFFECT_ITEM_THROW_BALL:
         switch (GetBallThrowableState())
         {
-            case BALL_THROW_UNABLE_TWO_MONS:
-                failStr = sText_CantThrowPokeBall_TwoMons;
-                cannotUse++;
-                break;
-            case BALL_THROW_UNABLE_NO_ROOM:
-                failStr = gText_BoxFull;
-                cannotUse++;
-                break;
-            case BALL_THROW_UNABLE_SEMI_INVULNERABLE:
-                failStr = sText_CantThrowPokeBall_SemiInvulnerable;
-                cannotUse++;
-                break;
-            case BALL_THROW_UNABLE_DISABLED_FLAG:
-                failStr = sText_CantThrowPokeBall_Disabled;
-                cannotUse++;
-                break;
+        case BALL_THROW_UNABLE_TWO_MONS:
+            failStr = sText_CantThrowPokeBall_TwoMons;
+            cannotUse = TRUE;
+            break;
+        case BALL_THROW_UNABLE_NO_ROOM:
+            failStr = gText_BoxFull;
+            cannotUse = TRUE;
+            break;
+        case BALL_THROW_UNABLE_SEMI_INVULNERABLE:
+            failStr = sText_CantThrowPokeBall_SemiInvulnerable;
+            cannotUse = TRUE;
+            break;
+        case BALL_THROW_UNABLE_DISABLED_FLAG:
+            failStr = sText_CantThrowPokeBall_Disabled;
+            cannotUse = TRUE;
+            break;
         }
-    }
-    // Max Mushrooms
-    if (battleUsage == EFFECT_ITEM_INCREASE_ALL_STATS)
-    {
-        u32 i;
-        for (i = 1; i < NUM_STATS; i++)
+        break;
+    case EFFECT_ITEM_INCREASE_ALL_STATS:
+        for (i = STAT_ATK; i < NUM_STATS; i++)
         {
             if (CompareStat(gBattlerInMenuId, i, MAX_STAT_STAGE, CMP_EQUAL))
             {
-                cannotUse++;
+                cannotUse = TRUE;
                 break;
             }
         }
+        break;
+    case EFFECT_ITEM_RESTORE_HP:
+        if (hp == 0 || hp == GetMonData(mon, MON_DATA_MAX_HP))
+            cannotUse = TRUE;
+        break;
+    case EFFECT_ITEM_CURE_STATUS:
+        if (!((GetMonData(mon, MON_DATA_STATUS) & GetItemStatus1Mask(itemId))
+            || (gPartyMenu.slotId == 0 && gBattleMons[gBattlerInMenuId].status2 & GetItemStatus2Mask(itemId))))
+            cannotUse = TRUE;
+        break;
+    case EFFECT_ITEM_HEAL_AND_CURE_STATUS:
+        if ((hp == 0 || hp == GetMonData(mon, MON_DATA_MAX_HP))
+            && !((GetMonData(mon, MON_DATA_STATUS) & GetItemStatus1Mask(itemId))
+            || (gPartyMenu.slotId == 0 && gBattleMons[gBattlerInMenuId].status2 & GetItemStatus2Mask(itemId))))
+            cannotUse = TRUE;
+        break;
+    case EFFECT_ITEM_REVIVE:
+        if (hp != 0)
+            cannotUse = TRUE;
+        break;
+    case EFFECT_ITEM_RESTORE_PP:
+        if (GetItemEffect(itemId)[6] == ITEM4_HEAL_PP)
+        {
+            for (i = 0; i < MAX_MON_MOVES; i++)
+            {
+                if (GetMonData(mon, MON_DATA_PP1 + i) < CalculatePPWithBonus(GetMonData(mon, MON_DATA_MOVE1 + i), GetMonData(mon, MON_DATA_PP_BONUSES), i));
+                    break;
+            }
+            if (i == MAX_MON_MOVES)
+                cannotUse = TRUE;
+        }
+        else if (GetMonData(mon, MON_DATA_PP1 + gPartyMenu.data1) == CalculatePPWithBonus(GetMonData(mon, MON_DATA_MOVE1 + gPartyMenu.data1), GetMonData(mon, MON_DATA_PP_BONUSES), gPartyMenu.data1))
+        {
+            cannotUse = TRUE;
+        }
+        break;
     }
 
     if (failStr != NULL)
         StringExpandPlaceholders(gStringVar4, failStr);
     else
         StringExpandPlaceholders(gStringVar4, gText_WontHaveEffect);
+
     return cannotUse;
 }
 
 void ItemUseInBattle_BagMenu(u8 taskId)
 {
-    if (CannotUseBagBattleItem(gSpecialVar_ItemId))
+    if (CannotUseItemsInBattle(gSpecialVar_ItemId, NULL))
     {
         if (!InBattlePyramid())
             DisplayItemMessage(taskId, FONT_NORMAL, gStringVar4, CloseItemMessage);
diff --git a/src/party_menu.c b/src/party_menu.c
index f333db02fb91..e97310058652 100644
--- a/src/party_menu.c
+++ b/src/party_menu.c
@@ -504,7 +504,6 @@ static bool8 SetUpFieldMove_Dive(void);
 void TryItemHoldFormChange(struct Pokemon *mon);
 static void ShowMoveSelectWindow(u8 slot);
 static void Task_HandleWhichMoveInput(u8 taskId);
-static bool32 CannotUsePartyBattleItem(u16 itemId, struct Pokemon* mon);
 
 // static const data
 #include "data/party_menu.h"
@@ -4557,70 +4556,11 @@ static bool8 IsItemFlute(u16 item)
     return FALSE;
 }
 
-static bool32 CannotUsePartyBattleItem(u16 itemId, struct Pokemon* mon)
-{
-    u8 i;
-    u8 cannotUse = FALSE;
-    u16 battleUsage = ItemId_GetBattleUsage(itemId);
-    u16 hp = GetMonData(mon, MON_DATA_HP);
-
-    // Embargo Check
-    if ((gPartyMenu.slotId == 0 && gStatuses3[B_POSITION_PLAYER_LEFT] & STATUS3_EMBARGO)
-        || (gPartyMenu.slotId == 1 && gStatuses3[B_POSITION_PLAYER_RIGHT] & STATUS3_EMBARGO))
-    {
-        return FALSE;
-    }
-    // Items that restore HP (Potions, Sitrus Berry, etc.)
-    if (battleUsage == EFFECT_ITEM_RESTORE_HP && (hp == 0 || hp == GetMonData(mon, MON_DATA_MAX_HP)))
-    {
-        cannotUse++;
-    }
-    // Items that cure status (Burn Heal, Awakening, etc.)
-    if (battleUsage == EFFECT_ITEM_CURE_STATUS
-        && !((GetMonData(mon, MON_DATA_STATUS) & GetItemStatus1Mask(itemId))
-        || (gPartyMenu.slotId == 0 && gBattleMons[gBattlerInMenuId].status2 & GetItemStatus2Mask(itemId))))
-    {
-        cannotUse++;
-    }
-    // Items that restore HP and cure status (Full Restore)
-    if (battleUsage == EFFECT_ITEM_HEAL_AND_CURE_STATUS
-        && (hp == 0 || hp == GetMonData(mon, MON_DATA_MAX_HP))
-        && !((GetMonData(mon, MON_DATA_STATUS) & GetItemStatus1Mask(itemId))
-        || (gPartyMenu.slotId == 0 && gBattleMons[gBattlerInMenuId].status2 & GetItemStatus2Mask(itemId))))
-    {
-        cannotUse++;
-    }
-    // Items that revive a party member
-    if (battleUsage == EFFECT_ITEM_REVIVE && hp != 0)
-    {
-        cannotUse++;
-    }
-    // Items that restore PP (Elixir, Ether, Leppa Berry)
-    if (battleUsage == EFFECT_ITEM_RESTORE_PP)
-    {
-        if (GetItemEffect(itemId)[6] == ITEM4_HEAL_PP)
-        {
-            for (i = 0; i < MAX_MON_MOVES; i++)
-            {
-                if (GetMonData(mon, MON_DATA_PP1 + i) < CalculatePPWithBonus(GetMonData(mon, MON_DATA_MOVE1 + i), GetMonData(mon, MON_DATA_PP_BONUSES), i));
-                    break;
-            }
-            if (i == MAX_MON_MOVES)
-                cannotUse++;
-        }
-        else if (GetMonData(mon, MON_DATA_PP1 + gPartyMenu.data1) == CalculatePPWithBonus(GetMonData(mon, MON_DATA_MOVE1 + gPartyMenu.data1), GetMonData(mon, MON_DATA_PP_BONUSES), gPartyMenu.data1))
-        {
-            cannotUse++;
-        }
-    }
-    return cannotUse;
-}
-
 // Battle scripts called in HandleAction_UseItem
 void ItemUseCB_BattleScript(u8 taskId, TaskFunc task)
 {
     struct Pokemon *mon = &gPlayerParty[gPartyMenu.slotId];
-    if (CannotUsePartyBattleItem(gSpecialVar_ItemId, mon))
+    if (CannotUseItemsInBattle(gSpecialVar_ItemId, mon))
     {
         gPartyMenuUseExitCallback = FALSE;
         PlaySE(SE_SELECT);
@@ -5129,7 +5069,7 @@ static void TryUseItemOnMove(u8 taskId)
     // In battle, set appropriate variables to be used in battle script.
     if (gMain.inBattle)
     {
-        if (CannotUsePartyBattleItem(gSpecialVar_ItemId, mon))
+        if (CannotUseItemsInBattle(gSpecialVar_ItemId, mon))
         {
             gPartyMenuUseExitCallback = FALSE;
             PlaySE(SE_SELECT);
diff --git a/test/battle/move_effect/burn_hit.c b/test/battle/move_effect/burn_hit.c
index 627a051a53c5..5c5dfa3d6035 100644
--- a/test/battle/move_effect/burn_hit.c
+++ b/test/battle/move_effect/burn_hit.c
@@ -38,3 +38,32 @@ SINGLE_BATTLE_TEST("Ember cannot burn a Fire-type Pokémon")
         }
     }
 }
+
+#if B_STATUS_TYPE_IMMUNITY > GEN_1
+SINGLE_BATTLE_TEST("Scald should burn a Water-type Pokémon")
+#else
+SINGLE_BATTLE_TEST("Scald shouldn't burn a Water-type Pokémon")
+#endif
+{
+    GIVEN {
+        ASSUME(gSpeciesInfo[SPECIES_SQUIRTLE].types[0] == TYPE_WATER);
+        ASSUME(gBattleMoves[MOVE_SCALD].effect == EFFECT_BURN_HIT);
+        ASSUME(gBattleMoves[MOVE_SCALD].type == TYPE_WATER);
+        PLAYER(SPECIES_SQUIRTLE);
+        OPPONENT(SPECIES_SQUIRTLE);
+    } WHEN {
+        TURN { MOVE(player, MOVE_SCALD); }
+    } SCENE {
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_SCALD, player);
+        HP_BAR(opponent);
+        #if B_STATUS_TYPE_IMMUNITY > GEN_1
+            ANIMATION(ANIM_TYPE_STATUS, B_ANIM_STATUS_BRN, opponent);
+            STATUS_ICON(opponent, burn: TRUE);
+        #else
+            NONE_OF {
+                ANIMATION(ANIM_TYPE_STATUS, B_ANIM_STATUS_BRN, opponent);
+                STATUS_ICON(opponent, burn: TRUE);
+            }
+        #endif
+    }
+}
diff --git a/test/battle/move_effect/freeze_hit.c b/test/battle/move_effect/freeze_hit.c
index 4c9ff557e414..991acc5da6d0 100644
--- a/test/battle/move_effect/freeze_hit.c
+++ b/test/battle/move_effect/freeze_hit.c
@@ -66,3 +66,32 @@ SINGLE_BATTLE_TEST("Blizzard bypasses accuracy checks in Hail and Snow")
         NOT MESSAGE("Wobbuffet's attack missed!");
     }
 }
+
+#if B_STATUS_TYPE_IMMUNITY > GEN_1
+SINGLE_BATTLE_TEST("Freezing Glare should freeze Psychic-types")
+#else
+SINGLE_BATTLE_TEST("Freezing Glare shouldn't freeze Psychic-types")
+#endif
+{
+    GIVEN {
+        ASSUME(gSpeciesInfo[SPECIES_ARTICUNO_GALARIAN].types[0] == TYPE_PSYCHIC);
+        ASSUME(gBattleMoves[MOVE_FREEZING_GLARE].effect == EFFECT_FREEZE_HIT);
+        ASSUME(gBattleMoves[MOVE_FREEZING_GLARE].type == TYPE_PSYCHIC);
+        PLAYER(SPECIES_ARTICUNO_GALARIAN);
+        OPPONENT(SPECIES_ARTICUNO_GALARIAN);
+    } WHEN {
+        TURN { MOVE(player, MOVE_FREEZING_GLARE); }
+    } SCENE {
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_FREEZING_GLARE, player);
+        HP_BAR(opponent);
+        #if B_STATUS_TYPE_IMMUNITY > GEN_1
+            ANIMATION(ANIM_TYPE_STATUS, B_ANIM_STATUS_FRZ, opponent);
+            STATUS_ICON(opponent, freeze: TRUE);
+        #else
+            NONE_OF {
+                ANIMATION(ANIM_TYPE_STATUS, B_ANIM_STATUS_FRZ, opponent);
+                STATUS_ICON(opponent, freeze: TRUE);
+            }
+        #endif
+    }
+}
diff --git a/test/battle/move_effect/paralyze_hit.c b/test/battle/move_effect/paralyze_hit.c
index c2fa440be144..24ae4bff9834 100644
--- a/test/battle/move_effect/paralyze_hit.c
+++ b/test/battle/move_effect/paralyze_hit.c
@@ -39,3 +39,32 @@ SINGLE_BATTLE_TEST("Thunder Shock cannot paralyze an Electric-type")
         }
     }
 }
+
+#if B_STATUS_TYPE_IMMUNITY > GEN_1
+SINGLE_BATTLE_TEST("Body Slam should paralyze Normal-types")
+#else
+SINGLE_BATTLE_TEST("Body Slam shouldn't paralyze Normal-types")
+#endif
+{
+    GIVEN {
+        ASSUME(gSpeciesInfo[SPECIES_TAUROS].types[0] == TYPE_NORMAL);
+        ASSUME(gBattleMoves[MOVE_BODY_SLAM].effect == EFFECT_PARALYZE_HIT);
+        ASSUME(gBattleMoves[MOVE_BODY_SLAM].type == TYPE_NORMAL);
+        PLAYER(SPECIES_TAUROS);
+        OPPONENT(SPECIES_TAUROS);
+    } WHEN {
+        TURN { MOVE(player, MOVE_BODY_SLAM); }
+    } SCENE {
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_BODY_SLAM, player);
+        HP_BAR(opponent);
+        #if B_STATUS_TYPE_IMMUNITY > GEN_1
+            ANIMATION(ANIM_TYPE_STATUS, B_ANIM_STATUS_PRZ, opponent);
+            STATUS_ICON(opponent, paralysis: TRUE);
+        #else
+            NONE_OF {
+                ANIMATION(ANIM_TYPE_STATUS, B_ANIM_STATUS_PRZ, opponent);
+                STATUS_ICON(opponent, paralysis: TRUE);
+            }
+        #endif
+    }
+}