diff --git a/Makefile.mak b/Makefile.mak
index 577433ca..9326a7d8 100644
--- a/Makefile.mak
+++ b/Makefile.mak
@@ -104,7 +104,7 @@ bin\th03\op.exe: th03\op_01.cpp bin\th03\op.obj bin\th03\inp_m_w.obj bin\th03\cd
 $**
 |
 
-bin\th03\main.exe: bin\th03\main.obj th03\main_01.cpp th03\sprite16.cpp
+bin\th03\main.exe: bin\th03\main.obj th03\main_01.cpp th03\mrs.cpp th03\sprite16.cpp
 	$(CC) $(CFLAGS) -ml -Z -DGAME=3 -nbin\th03\ -eMAIN.EXE @&&|
 $**
 |
diff --git a/th03/formats/mrs.cpp b/th03/formats/mrs.cpp
index 6312f5e5..4b472ee7 100644
--- a/th03/formats/mrs.cpp
+++ b/th03/formats/mrs.cpp
@@ -1,6 +1,9 @@
+#pragma codeseg SHARED
+
 #include "platform.h"
 #include "pc98.h"
 #include "planar.h"
+#include "th03/formats/hfliplut.h"
 #include "th03/formats/mrs.hpp"
 
 static const vram_byte_amount_t MRS_BYTE_W = (MRS_W / BYTE_DOTS);
@@ -17,3 +20,51 @@ struct mrs_t {
 };
 
 extern mrs_t far *mrs_images[MRS_SLOT_COUNT];
+
+// Points [reg_sgm]:[reg_off] to the alpha plane of the .MRS image in the
+// given [slot].
+#define mrs_slot_assign(reg_sgm, reg_off, slot) { \
+	_BX = slot; \
+	_BX <<= 2; \
+	__asm { l##reg_sgm reg_off, mrs_images[bx]; } \
+}
+
+void pascal mrs_hflip(int slot)
+{
+	_CX = sizeof(mrs_t);
+	mrs_slot_assign(es, di, slot);
+	reinterpret_cast<dots8_t near *>(_BX) = hflip_lut;
+
+	flip_dots_within_bytes: __asm {
+		mov 	al, es:[di];
+		xlat;
+		mov 	es:[di], al;
+		inc 	di;
+		loop	flip_dots_within_bytes;
+	}
+
+	_CX = (sizeof(mrs_t) / MRS_BYTE_W);
+	/* vram_byte_amount_t offset_y */ _BX = 0;
+
+	flip_bytes: {
+		// Assumes that the offset part of all image pointers is 0. Storing
+		// segment pointers in [mrs_images] would have been clearer in this
+		// case...
+		/* vram_byte_amount_t offset_left  */ _DI = 0;
+		/* vram_byte_amount_t offset_right */ _SI = (MRS_BYTE_W - 1);
+		do {
+			__asm {
+				mov al, es:[bx+di]
+				mov dl, es:[bx+si]
+				mov es:[bx+si], al
+				mov es:[bx+di], dl
+			}
+			_SI--;
+			_DI++;
+		} while(_DI <= ((MRS_BYTE_W / 2) - 1));
+		_BX += MRS_BYTE_W;
+		__asm { loop flip_bytes; }
+	}
+}
+
+#pragma codestring "\x90"
diff --git a/th03/formats/mrs.hpp b/th03/formats/mrs.hpp
index ef8ef6f5..ad9e19d4 100644
--- a/th03/formats/mrs.hpp
+++ b/th03/formats/mrs.hpp
@@ -6,4 +6,7 @@
 static const int MRS_SLOT_COUNT = 8;
 static const pixel_t MRS_W = 288;
 static const pixel_t MRS_H = 184;
+
+// Persistently flips the image in [slot] horizontally, using the [hflip_lut].
+void pascal mrs_hflip(int slot);
 /// ---------------------------------------------------------------------------
diff --git a/th03/mrs.cpp b/th03/mrs.cpp
new file mode 100644
index 00000000..54641495
--- /dev/null
+++ b/th03/mrs.cpp
@@ -0,0 +1 @@
+#include "th03/formats/mrs.cpp"
diff --git a/th03_main.asm b/th03_main.asm
index 5d596d33..c2670e35 100644
--- a/th03_main.asm
+++ b/th03_main.asm
@@ -1583,10 +1583,8 @@ sub_A4A1	proc near
 
 		push	bp
 		mov	bp, sp
-		push	1
-		call	sub_F0A6
-		push	3
-		call	sub_F0A6
+		call	@mrs_hflip$qi pascal, 1
+		call	@mrs_hflip$qi pascal, 3
 		call	respal_get_palettes
 		call	far ptr	palette_show
 		nopcall	sub_A378
@@ -9152,60 +9150,7 @@ sub_EFF4	endp
 
 ; ---------------------------------------------------------------------------
 		nop
-
-; =============== S U B	R O U T	I N E =======================================
-
-; Attributes: bp-based frame
-
-sub_F0A6	proc far
-
-arg_0		= word ptr  6
-
-		push	bp
-		mov	bp, sp
-
-loc_F0A9:
-		push	si
-		push	di
-		mov	cx, 8160h
-		mov	bx, [bp+arg_0]
-		shl	bx, 2
-		les	di, _mrs_images[bx]
-		mov	bx, offset _hflip_lut
-
-loc_F0BB:
-		mov	al, es:[di]
-		xlat
-		mov	es:[di], al
-		inc	di
-		loop	loc_F0BB
-		mov	cx, 398h
-		xor	bx, bx
-
-loc_F0CA:
-		xor	di, di
-		mov	si, 23h	; '#'
-
-loc_F0CF:
-		mov	al, es:[bx+di]
-		mov	dl, es:[bx+si]
-		mov	es:[bx+si], al
-		mov	es:[bx+di], dl
-		dec	si
-		inc	di
-		cmp	di, 11h
-		jbe	short loc_F0CF
-		add	bx, 24h	; '$'
-		loop	loc_F0CA
-		pop	di
-		pop	si
-		pop	bp
-		retf	2
-sub_F0A6	endp
-
-; ---------------------------------------------------------------------------
-		nop
-
+	extern @MRS_HFLIP$QI:proc
 	SPRITE16_SPRITES_COMMIT procdesc pascal far
 	SPRITE16_PUT procdesc pascal far \
 		left:word, screen_top:word, sprite_offset:word