diff --git a/common/filetype.c b/common/filetype.c
index 8652f1d..1ff3dd2 100644
--- a/common/filetype.c
+++ b/common/filetype.c
@@ -151,6 +151,28 @@
 	return filetype_mbr;
 }
 
+enum filetype file_detect_partition_table(const void *_buf, size_t bufsize)
+{
+	const u8 *buf8 = _buf;
+	enum filetype type;
+
+	if (bufsize < 512)
+		return filetype_unknown;
+
+	/*
+	 * EFI GPT need to be detected before MBR otherwise
+	 * we will detect a MBR
+	 */
+	if (bufsize >= 520 && is_gpt_valid(buf8))
+		return filetype_gpt;
+
+	type = is_fat_or_mbr(buf8, NULL);
+	if (type != filetype_unknown)
+		return type;
+
+	return filetype_unknown;
+}
+
 enum filetype file_detect_type(const void *_buf, size_t bufsize)
 {
 	const u32 *buf = _buf;
@@ -204,21 +226,11 @@
 	if (bufsize < 512)
 		return filetype_unknown;
 
-	/*
-	 * EFI GPT need to be detected before MBR otherwise
-	 * we will detect a MBR
-	 */
-	if (bufsize >= 520 && is_gpt_valid(buf8))
-		return filetype_gpt;
-
-	type = is_fat_or_mbr(buf8, NULL);
+	type = file_detect_partition_table(_buf, bufsize);
 	if (type != filetype_unknown)
 		return type;
 
-	if (bufsize < 1536)
-		return filetype_unknown;
-
-	if (buf16[512 + 28] == le16_to_cpu(0xef53))
+	if (bufsize >= 1536 && buf16[512 + 28] == le16_to_cpu(0xef53))
 		return filetype_ext;
 
 	return filetype_unknown;
diff --git a/include/filetype.h b/include/filetype.h
index 78ca5d2..ee777ac 100644
--- a/include/filetype.h
+++ b/include/filetype.h
@@ -31,6 +31,7 @@
 
 const char *file_type_to_string(enum filetype f);
 const char *file_type_to_short_string(enum filetype f);
+enum filetype file_detect_partition_table(const void *_buf, size_t bufsize);
 enum filetype file_detect_type(const void *_buf, size_t bufsize);
 enum filetype file_name_detect_type(const char *filename);
 enum filetype is_fat_or_mbr(const unsigned char *sector, unsigned long *bootsec);