diff --git a/src/sound_type.h b/src/sound_type.h
index 76fe25139e..5be10de21b 100644
--- a/src/sound_type.h
+++ b/src/sound_type.h
@@ -13,7 +13,7 @@
 #define SOUND_TYPE_H
 
 struct SoundEntry {
-	uint8 file_slot;
+	uint file_slot;
 	size_t file_offset;
 	size_t file_size;
 	uint16 rate;
diff --git a/src/spritecache.cpp b/src/spritecache.cpp
index e0aab931b3..91eae15970 100644
--- a/src/spritecache.cpp
+++ b/src/spritecache.cpp
@@ -440,7 +440,7 @@ static void *ReadRecolourSprite(uint16 file_slot, uint num)
  */
 static void *ReadSprite(const SpriteCache *sc, SpriteID id, SpriteType sprite_type, AllocatorProc *allocator)
 {
-	uint8 file_slot = sc->file_slot;
+	uint file_slot = sc->file_slot;
 	size_t file_pos = sc->file_pos;
 
 	assert(sprite_type != ST_RECOLOUR);
@@ -852,7 +852,7 @@ uint32 GetSpriteMainColour(SpriteID sprite_id, PaletteID palette_id)
 
 	const byte * const remap = (palette_id == PAL_NONE ? NULL : GetNonSprite(GB(palette_id, 0, PALETTE_WIDTH), ST_RECOLOUR) + 1);
 
-	uint8 file_slot = sc->file_slot;
+	uint file_slot = sc->file_slot;
 	size_t file_pos = sc->file_pos;
 
 	SpriteLoader::Sprite sprites[ZOOM_LVL_COUNT];
diff --git a/src/spriteloader/grf.cpp b/src/spriteloader/grf.cpp
index b21e70b1db..0f54a9eadc 100644
--- a/src/spriteloader/grf.cpp
+++ b/src/spriteloader/grf.cpp
@@ -42,7 +42,7 @@ DECLARE_ENUM_AS_BIT_SET(SpriteColourComponent)
  * @param line the line where the error occurs.
  * @return always false (to tell loading the sprite failed)
  */
-static bool WarnCorruptSprite(uint8 file_slot, size_t file_pos, int line)
+static bool WarnCorruptSprite(uint file_slot, size_t file_pos, int line)
 {
 	static byte warning_level = 0;
 	if (warning_level == 0) {
@@ -67,7 +67,7 @@ static bool WarnCorruptSprite(uint8 file_slot, size_t file_pos, int line)
  * @param container_format Container format of the GRF this sprite is in.
  * @return True if the sprite was successfully loaded.
  */
-bool DecodeSingleSprite(SpriteLoader::Sprite *sprite, uint8 file_slot, size_t file_pos, SpriteType sprite_type, int64 num, byte type, ZoomLevel zoom_lvl, byte colour_fmt, byte container_format)
+bool DecodeSingleSprite(SpriteLoader::Sprite *sprite, uint file_slot, size_t file_pos, SpriteType sprite_type, int64 num, byte type, ZoomLevel zoom_lvl, byte colour_fmt, byte container_format)
 {
 	AutoFreePtr<byte> dest_orig(MallocT<byte>(num));
 	byte *dest = dest_orig;
@@ -215,7 +215,7 @@ bool DecodeSingleSprite(SpriteLoader::Sprite *sprite, uint8 file_slot, size_t fi
 	return true;
 }
 
-uint8 LoadSpriteV1(SpriteLoader::Sprite *sprite, uint8 file_slot, size_t file_pos, SpriteType sprite_type, bool load_32bpp)
+uint8 LoadSpriteV1(SpriteLoader::Sprite *sprite, uint file_slot, size_t file_pos, SpriteType sprite_type, bool load_32bpp)
 {
 	/* Check the requested colour depth. */
 	if (load_32bpp) return 0;
@@ -251,7 +251,7 @@ uint8 LoadSpriteV1(SpriteLoader::Sprite *sprite, uint8 file_slot, size_t file_po
 	return 0;
 }
 
-uint8 LoadSpriteV2(SpriteLoader::Sprite *sprite, uint8 file_slot, size_t file_pos, SpriteType sprite_type, bool load_32bpp)
+uint8 LoadSpriteV2(SpriteLoader::Sprite *sprite, uint file_slot, size_t file_pos, SpriteType sprite_type, bool load_32bpp)
 {
 	static const ZoomLevel zoom_lvl_map[6] = {ZOOM_LVL_OUT_4X, ZOOM_LVL_NORMAL, ZOOM_LVL_OUT_2X, ZOOM_LVL_OUT_8X, ZOOM_LVL_OUT_16X, ZOOM_LVL_OUT_32X};
 
@@ -325,7 +325,7 @@ uint8 LoadSpriteV2(SpriteLoader::Sprite *sprite, uint8 file_slot, size_t file_po
 	return loaded_sprites;
 }
 
-uint8 SpriteLoaderGrf::LoadSprite(SpriteLoader::Sprite *sprite, uint8 file_slot, size_t file_pos, SpriteType sprite_type, bool load_32bpp)
+uint8 SpriteLoaderGrf::LoadSprite(SpriteLoader::Sprite *sprite, uint file_slot, size_t file_pos, SpriteType sprite_type, bool load_32bpp)
 {
 	if (this->container_ver >= 2) {
 		return LoadSpriteV2(sprite, file_slot, file_pos, sprite_type, load_32bpp);
diff --git a/src/spriteloader/grf.hpp b/src/spriteloader/grf.hpp
index 4081a9f337..20543a5e6a 100644
--- a/src/spriteloader/grf.hpp
+++ b/src/spriteloader/grf.hpp
@@ -19,7 +19,7 @@ class SpriteLoaderGrf : public SpriteLoader {
 	byte container_ver;
 public:
 	SpriteLoaderGrf(byte container_ver) : container_ver(container_ver) {}
-	uint8 LoadSprite(SpriteLoader::Sprite *sprite, uint8 file_slot, size_t file_pos, SpriteType sprite_type, bool load_32bpp);
+	uint8 LoadSprite(SpriteLoader::Sprite *sprite, uint file_slot, size_t file_pos, SpriteType sprite_type, bool load_32bpp);
 };
 
 #endif /* SPRITELOADER_GRF_HPP */
diff --git a/src/spriteloader/spriteloader.hpp b/src/spriteloader/spriteloader.hpp
index 060e72d16b..7927fdfeef 100644
--- a/src/spriteloader/spriteloader.hpp
+++ b/src/spriteloader/spriteloader.hpp
@@ -61,7 +61,7 @@ public:
 	 * @param load_32bpp  True if 32bpp sprites should be loaded, false for a 8bpp sprite.
 	 * @return Bit mask of the zoom levels successfully loaded or 0 if no sprite could be loaded.
 	 */
-	virtual uint8 LoadSprite(SpriteLoader::Sprite *sprite, uint8 file_slot, size_t file_pos, SpriteType sprite_type, bool load_32bpp) = 0;
+	virtual uint8 LoadSprite(SpriteLoader::Sprite *sprite, uint file_slot, size_t file_pos, SpriteType sprite_type, bool load_32bpp) = 0;
 
 	virtual ~SpriteLoader() { }
 };