diff --git a/th04/boss/reset.cpp b/th04/boss/reset.cpp
new file mode 100644
index 00000000..7b02617d
--- /dev/null
+++ b/th04/boss/reset.cpp
@@ -0,0 +1,18 @@
+char boss_phase_timed_out = 0;
+
+void pascal near boss_reset(void)
+{
+	boss_update = nullsub_1;
+	boss_fg_render = nullfunc_near;
+#if GAME == 5
+	boss_custombullets_render = nullfunc_near;
+#endif
+	boss.phase = 0;
+	boss.mode = 0;
+	boss.mode_change = 0;
+	boss.phase_frame = 0;
+	boss.pos.velocity.set(0, 0);
+	boss.damage_this_frame = 0;
+	explosions_small_reset();
+	boss_phase_timed_out = 1;
+}
diff --git a/th04/shared.hpp b/th04/shared.hpp
index 33392b2e..5fce831f 100644
--- a/th04/shared.hpp
+++ b/th04/shared.hpp
@@ -107,6 +107,8 @@ extern boss_stuff_t boss;
 extern SPPoint boss_hitbox_radius;
 
 // Callbacks
+extern  farfunc_t_near boss_update;
+extern nearfunc_t_near boss_fg_render;
 extern  farfunc_t_near boss_update_func;
 extern nearfunc_t_near boss_backdrop_colorfill;
 extern nearfunc_t_near boss_bg_render_func;
@@ -116,6 +118,9 @@ extern nearfunc_t_near boss_fg_render_func;
 	void pascal  far name##_update(void); \
 	void pascal near name##_bg_render(void); \
 	void pascal near name##_fg_render(void);
+
+// Explosions
+void pascal far explosions_small_reset(void);
 // ------
 
 /// Score
diff --git a/th05/main_01.cpp b/th05/main_01.cpp
index 006e8a99..2660f782 100644
--- a/th05/main_01.cpp
+++ b/th05/main_01.cpp
@@ -16,10 +16,7 @@ void pascal near playfield_fillm_64_56_256_256(void);
 void pascal near playfield_fillm_0_0_384_192__1(void);
 void pascal near playfield_fillm_0_104_384_192(void);
 
-char boss_phase_timed_out = 0;
-
-void pascal near boss_reset(void);
-
+#include "th04/boss/reset.cpp"
 #include "th04/formats/bb_stage.c"
 #include "th05/stage/setup.cpp"
 
diff --git a/th05/th05.hpp b/th05/th05.hpp
index 09b97411..0916a1ee 100644
--- a/th05/th05.hpp
+++ b/th05/th05.hpp
@@ -29,6 +29,9 @@ MIDBOSS_DEC(x);
 
 /// Bosses
 /// ------
+// Callbacks
+extern nearfunc_t_near boss_custombullets_render;
+
 extern unsigned int boss_sprite_left;
 extern unsigned int boss_sprite_right;
 extern unsigned int boss_sprite_stay;
diff --git a/th05_main.asm b/th05_main.asm
index 65d91d6a..6341e7b8 100644
--- a/th05_main.asm
+++ b/th05_main.asm
@@ -17862,30 +17862,7 @@ loc_144C4:
 		jmp	loc_14435
 score_update_and_render	endp
 
-
-; =============== S U B	R O U T	I N E =======================================
-
-; Attributes: bp-based frame
-public BOSS_RESET
-boss_reset	proc near
-		push	bp
-		mov	bp, sp
-		setfarfp	_boss_update, nullsub_1
-		mov	_boss_fg_render, offset nullfunc_near
-		mov	_boss_custombullets_render, offset nullfunc_near
-		mov	_boss_phase, 0
-		mov	_boss_mode, 0
-		mov	_boss_mode_change, 0
-		mov	_boss_phase_frame, 0
-		mov	_boss_pos.velocity.x, 0
-		mov	_boss_pos.velocity.y, 0
-		mov	_boss_damage_this_frame, 0
-		call	explosions_small_reset
-		mov	_boss_phase_timed_out, 1
-		pop	bp
-		retn
-boss_reset	endp
-
+	BOSS_RESET procdesc near
 	BB_STAGE_LOAD procdesc near
 	BB_STAGE_FREE procdesc near
 	STAGE1_SETUP procdesc near