diff --git a/sfall/FalloutEngine/Functions_def.h b/sfall/FalloutEngine/Functions_def.h
index f984fe60..771d0709 100644
--- a/sfall/FalloutEngine/Functions_def.h
+++ b/sfall/FalloutEngine/Functions_def.h
@@ -21,7 +21,7 @@ WRAP_WATCOM_FFUNC7(long, createWindow, const char*, winName, long, x, long, y, l
 WRAP_WATCOM_FFUNC3(void, display_inventory, long, inventoryOffset, long, visibleOffset, long, mode)
 WRAP_WATCOM_FFUNC4(void, display_target_inventory, long, inventoryOffset, long, visibleOffset, DWORD*, targetInventory, long, mode)
 WRAP_WATCOM_FFUNC3(FrmFrameData*, frame_ptr, FrmHeaderData*, frm, long, frame, long, direction)
-WRAP_WATCOM_FFUNC7(void, make_straight_path_func, fo::GameObject*, objFrom, DWORD, tileFrom, DWORD, tileTo, void*, rotationPtr, DWORD*, result, long, flags, void*, func)
+WRAP_WATCOM_FFUNC7(void, make_straight_path_func, GameObject*, objFrom, DWORD, tileFrom, DWORD, tileTo, void*, rotationPtr, DWORD*, result, long, flags, void*, func)
 WRAP_WATCOM_FFUNC3(long, object_under_mouse, long, crSwitch, long, inclDude, long, elevation)
 WRAP_WATCOM_FFUNC3(long, scr_get_local_var, long, sid, long, varId, long*, value)
 WRAP_WATCOM_FFUNC3(long, scr_set_local_var, long, sid, long, varId, long, value)
@@ -93,7 +93,9 @@ WRAP_WATCOM_FUNC0(long, new_obj_id)
 // calculates bounding box (rectangle) for a given object
 WRAP_WATCOM_FUNC2(void, obj_bound, GameObject*, object, BoundRect*, boundRect)
 WRAP_WATCOM_FUNC2(long, obj_erase_object, GameObject*, object, BoundRect*, boundRect)
-WRAP_WATCOM_FUNC2(long, obj_pid_new, fo::GameObject*, object, long, pid)
+WRAP_WATCOM_FUNC0(GameObject*, obj_find_first)
+WRAP_WATCOM_FUNC0(GameObject*, obj_find_next)
+WRAP_WATCOM_FUNC2(long, obj_pid_new, GameObject*, object, long, pid)
 // checks/unjams jammed locks
 WRAP_WATCOM_FUNC1(long, obj_lock_is_jammed, GameObject*, object)
 WRAP_WATCOM_FUNC1(void, obj_unjam_lock, GameObject*, object)
diff --git a/sfall/Modules/Objects.cpp b/sfall/Modules/Objects.cpp
index 7f73f6d5..cde4f9ef 100644
--- a/sfall/Modules/Objects.cpp
+++ b/sfall/Modules/Objects.cpp
@@ -83,6 +83,34 @@ pickNewID: // skip PM range (18000 - 83535)
 	}
 }
 
+// Reassigns object IDs to all critters upon first loading a map
+static void map_fix_critter_id() {
+	long npcStartID = 4096;
+	fo::GameObject* obj = fo::func::obj_find_first();
+	while (obj) {
+		if (obj->Type() == fo::OBJ_TYPE_CRITTER && obj->id < PLAYER_ID) {
+			obj->id = npcStartID++;
+		}
+		obj = fo::func::obj_find_next();
+	}
+}
+
+static void __declspec(naked) map_load_file_hack() {
+	__asm {
+		jz   mapVirgin;
+		retn;
+mapVirgin:
+		call fo::funcoffs::wmMapIsSaveable_;
+		test eax, eax;
+		jnz  saveable;
+		retn;
+saveable:
+		call map_fix_critter_id;
+		xor  eax, eax; // set ZF
+		retn;
+	}
+}
+
 void Objects::SetAutoUnjamLockTime(DWORD time) {
 	if (!unjamTimeState) {
 		BlockCall(0x4A364A); // disable auto unjam at midnight
@@ -139,6 +167,10 @@ void Objects::init() {
 	SafeWrite8(0x4A38B3, 0x90); // fix ID increment
 
 	MakeCall(0x477A0E, item_identical_hack); // don't put item with unique ID to items stack
+
+	// Fix mapper bug by reassigning object IDs to critters (for maps not yet visited)
+	MakeCall(0x482E6B, map_load_file_hack);
+	SafeWrite8(0x482E71, 0x85); // jz > jnz
 }
 
 }