diff --git a/libretro-common/formats/libchdr/libchdr_chd.c b/libretro-common/formats/libchdr/libchdr_chd.c
index 7ac16a5e4b..4713dd6fc5 100644
--- a/libretro-common/formats/libchdr/libchdr_chd.c
+++ b/libretro-common/formats/libchdr/libchdr_chd.c
@@ -1335,7 +1335,7 @@ static UINT32 header_guess_unitbytes(chd_file *chd)
 {
 	/* look for hard disk metadata; if found, then the unit size == sector size */
 	char metadata[512];
-	int i0, i1, i2, i3;
+	unsigned int i0, i1, i2, i3;
 	if (chd_get_metadata(chd, HARD_DISK_METADATA_TAG, 0, metadata, sizeof(metadata), NULL, NULL, NULL) == CHDERR_NONE &&
 		sscanf(metadata, HARD_DISK_METADATA_FORMAT, &i0, &i1, &i2, &i3) == 4)
 		return i3;
diff --git a/libretro-common/include/libchdr/chd.h b/libretro-common/include/libchdr/chd.h
index 3c68f9c907..a21ee9dd52 100644
--- a/libretro-common/include/libchdr/chd.h
+++ b/libretro-common/include/libchdr/chd.h
@@ -212,7 +212,7 @@ extern "C" {
 
 /* standard hard disk metadata */
 #define HARD_DISK_METADATA_TAG		0x47444444	/* 'GDDD' */
-#define HARD_DISK_METADATA_FORMAT	"CYLS:%d,HEADS:%d,SECS:%d,BPS:%d"
+#define HARD_DISK_METADATA_FORMAT	"CYLS:%u,HEADS:%u,SECS:%u,BPS:%u"
 
 /* hard disk identify information */
 #define HARD_DISK_IDENT_METADATA_TAG 0x49444e54 /* 'IDNT' */