diff --git a/player/player.c b/player/player.c
index c648a3e..f39bfd9 100644
--- a/player/player.c
+++ b/player/player.c
@@ -49,12 +49,10 @@ void display() {
 #include "pocketlib.h"
 
 static void display() {
-    // ????
     VSync(VSYNC_COUNT);
     uint32_t *src = (uint32_t*)screen;
 	volatile unsigned int *dst = LCD_VRAM_ADRS;
-	int i = 32;
-	while (i--) {*dst++ = *src++;}
+	for (int i=32; i--;) {*dst++ = *src++;}
 }
 
 uint8_t	ROMByteAccess(unsigned char *addr)
diff --git a/tools/Makefile b/tools/Makefile
index e75de7c..3b4cae5 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -1,9 +1,11 @@
-all: ascii2sjis bin2mcs bmp2ps1b mcpad
+all: ascii2sjis bin2mcs bmp2ps1b mcpad bmp_to_1bit
 
 ascii2sjis: ascii2sjis.c
 bin2mcs: bin2mcs.c
 bmp2ps1b: bmp2ps1b.c
 mcpad: mcpad.c
+bmp_to_1bit: bmp_to_1bit.c
 
 clean:
-	rm -f ascii2sjis bin2mcs bmp2ps1b mcpad
\ No newline at end of file
+	rm -f ascii2sjis bin2mcs bmp2ps1b mcpad bmp_to_1bit
+	rm -f ascii2sjis.exe bin2mcs.exe bmp2ps1b.exe mcpad.exe bmp_to_1bit.exe
diff --git a/tools/ascii2sjis.exe b/tools/ascii2sjis.exe
deleted file mode 100644
index 159444f..0000000
Binary files a/tools/ascii2sjis.exe and /dev/null differ
diff --git a/tools/bin2mcs.exe b/tools/bin2mcs.exe
deleted file mode 100644
index 74fb7dc..0000000
Binary files a/tools/bin2mcs.exe and /dev/null differ
diff --git a/tools/bmp2ps1b.exe b/tools/bmp2ps1b.exe
deleted file mode 100644
index f83c3d3..0000000
Binary files a/tools/bmp2ps1b.exe and /dev/null differ
diff --git a/tools/bmp_to_1bit.c b/tools/bmp_to_1bit.c
new file mode 100644
index 0000000..82274b3
--- /dev/null
+++ b/tools/bmp_to_1bit.c
@@ -0,0 +1,91 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+typedef struct __attribute__((__packed__)) BMPHeader {
+    uint16_t type;              // Magic identifier: 0x4d42
+    uint32_t size;              // File size in bytes
+    uint16_t reserved1;         // Not used
+    uint16_t reserved2;         // Not used
+    uint32_t offset;            // Offset to image data in bytes from beginning of file
+    uint32_t dib_header_size;   // DIB Header size in bytes
+    int32_t  width_px;          // Width of the image
+    int32_t  height_px;         // Height of image
+    uint16_t num_planes;        // Number of color planes
+    uint16_t bits_per_pixel;    // Bits per pixel
+    uint32_t compression;       // Compression type
+    uint32_t image_size_bytes;  // Image size in bytes
+    int32_t  x_resolution_ppm;  // Pixels per meter
+    int32_t  y_resolution_ppm;  // Pixels per meter
+    uint32_t num_colors;        // Number of colors
+    uint32_t important_colors;  // Important colors
+} BMPHeader;
+
+
+int main (int argc, char* argv[])
+{
+    FILE* in, *out;
+    if(argc < 3) {
+        printf("Usage: %s <input.bmp> <output.bmp>\n", argv[0]);
+        return 1;
+    }
+
+    in = fopen(argv[1], "rb");
+    if(!in) {
+        printf("Could not open input file.\n");
+        return 1;
+    }
+
+    out = fopen(argv[2], "wb");
+    if(!out) {
+        printf("Could not open output file.\n");
+        return 1;
+    }
+
+    BMPHeader in_header = {0};
+    fread(&in_header, sizeof(BMPHeader), 1, in);
+
+    fseek(in, in_header.offset, SEEK_SET);
+    uint8_t* px = malloc(in_header.image_size_bytes);
+    fread(px, in_header.image_size_bytes, 1, in);
+    fclose(in);
+
+    printf("%d x %d\n", in_header.width_px, in_header.height_px);
+    printf("bpp: %d\n", in_header.bits_per_pixel);
+
+    uint8_t* out_buffer = malloc(32 * 32 / 8);
+    for(int out_y = 0; out_y < 32; out_y++) {
+        for(int out_x = 0; out_x < 32; out_x++) {
+            // input is bigger than output
+            // so we need to skip some pixels
+            int in_x = out_x * in_header.width_px / 32;
+            int in_y = out_y * in_header.height_px / 32;
+            int in_offset = (in_y * in_header.width_px + in_x) * 3;
+            uint8_t v = (px[in_offset + 2] + px[in_offset + 1] + px[in_offset + 0]) / 3;
+            int out_offset = out_y * 32 / 8 + out_x / 8;
+            if(v > 127) {
+                out_buffer[out_offset] |= 1 << (7 - out_x % 8);
+            } else {
+                out_buffer[out_offset] &= ~(1 << (7 - out_x % 8));
+            }
+        }
+    }
+    free(px);
+    
+    BMPHeader out_header = {0};
+    out_header.type = 0x4d42;
+    out_header.size = sizeof(BMPHeader) + 32 * 32 / 8;
+    out_header.offset = sizeof(BMPHeader);
+    out_header.dib_header_size = sizeof(BMPHeader) - 14;
+    out_header.width_px = 32;
+    out_header.height_px = 32;
+    out_header.bits_per_pixel = 1;
+    out_header.image_size_bytes = 32 * 32 / 8;
+    out_header.num_colors = 2;
+    out_header.important_colors = 2;
+
+    fwrite(&out_header, sizeof(BMPHeader), 1, out);
+    fwrite(out_buffer, out_header.image_size_bytes, 1, out);
+    fclose(out);
+    free(out_buffer);
+}
diff --git a/tools/bmp_to_1bit.exe b/tools/bmp_to_1bit.exe
deleted file mode 100644
index 4cded03..0000000
Binary files a/tools/bmp_to_1bit.exe and /dev/null differ
diff --git a/tools/bmp_to_1bit.py b/tools/bmp_to_1bit.py
deleted file mode 100755
index 280cc76..0000000
--- a/tools/bmp_to_1bit.py
+++ /dev/null
@@ -1,8 +0,0 @@
-#!/bin/python3
-import sys
-from PIL import Image
-
-img = Image.open(sys.argv[1])
-img = img.convert("1", dither=Image.Dither.NONE)
-img = img.resize((32,32), Image.Resampling.NEAREST)
-img.save(sys.argv[2])
diff --git a/tools/mcpad.exe b/tools/mcpad.exe
deleted file mode 100644
index 1c0d2d1..0000000
Binary files a/tools/mcpad.exe and /dev/null differ