diff --git a/include/grub/gpt_partition.h b/include/grub/gpt_partition.h
index 3cac6df32..df076ca64 100644
--- a/include/grub/gpt_partition.h
+++ b/include/grub/gpt_partition.h
@@ -23,33 +23,35 @@
 #include <grub/partition.h>
 #include <grub/msdos_partition.h>
 
-struct grub_gpt_part_type
+struct grub_gpt_guid
 {
   grub_uint32_t data1;
   grub_uint16_t data2;
   grub_uint16_t data3;
   grub_uint8_t data4[8];
 } __attribute__ ((aligned(8)));
-typedef struct grub_gpt_part_type grub_gpt_part_type_t;
+typedef struct grub_gpt_guid grub_gpt_guid_t;
+typedef struct grub_gpt_guid grub_gpt_part_type_t;
+
+#define GRUB_GPT_GUID_INIT(a, b, c, d1, d2, d3, d4, d5, d6, d7, d8)  \
+  {					\
+    grub_cpu_to_le32_compile_time (a),	\
+    grub_cpu_to_le16_compile_time (b),	\
+    grub_cpu_to_le16_compile_time (c),	\
+    { d1, d2, d3, d4, d5, d6, d7, d8 }	\
+  }
 
 #define GRUB_GPT_PARTITION_TYPE_EMPTY \
-  { 0x0, 0x0, 0x0, \
-    { 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 } \
-  }
+  GRUB_GPT_GUID_INIT (0x0, 0x0, 0x0,  \
+      0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
 
 #define GRUB_GPT_PARTITION_TYPE_BIOS_BOOT \
-  { grub_cpu_to_le32_compile_time (0x21686148), \
-      grub_cpu_to_le16_compile_time (0x6449), \
-      grub_cpu_to_le16_compile_time (0x6e6f),	       \
-    { 0x74, 0x4e, 0x65, 0x65, 0x64, 0x45, 0x46, 0x49 } \
-  }
+  GRUB_GPT_GUID_INIT (0x21686148, 0x6449, 0x6e6f, \
+      0x74, 0x4e, 0x65, 0x65, 0x64, 0x45, 0x46, 0x49)
 
 #define GRUB_GPT_PARTITION_TYPE_LDM \
-  { grub_cpu_to_le32_compile_time (0x5808C8AAU),\
-      grub_cpu_to_le16_compile_time (0x7E8F), \
-      grub_cpu_to_le16_compile_time (0x42E0),	       \
-	{ 0x85, 0xD2, 0xE1, 0xE9, 0x04, 0x34, 0xCF, 0xB3 }	\
-  }
+  GRUB_GPT_GUID_INIT (0x5808c8aa, 0x7e8f, 0x42e0, \
+      0x85, 0xd2, 0xe1, 0xe9, 0x04, 0x34, 0xcf, 0xb3)
 
 #define GRUB_GPT_HEADER_MAGIC \
   { 0x45, 0x46, 0x49, 0x20, 0x50, 0x41, 0x52, 0x54 }
@@ -68,7 +70,7 @@ struct grub_gpt_header
   grub_uint64_t alternate_lba;
   grub_uint64_t start;
   grub_uint64_t end;
-  grub_uint8_t guid[16];
+  grub_gpt_guid_t guid;
   grub_uint64_t partitions;
   grub_uint32_t maxpart;
   grub_uint32_t partentry_size;
@@ -78,7 +80,7 @@ struct grub_gpt_header
 struct grub_gpt_partentry
 {
   grub_gpt_part_type_t type;
-  grub_uint8_t guid[16];
+  grub_gpt_guid_t guid;
   grub_uint64_t start;
   grub_uint64_t end;
   grub_uint64_t attrib;
diff --git a/tests/gpt_unit_test.c b/tests/gpt_unit_test.c
index 83198bebf..86e4364a5 100644
--- a/tests/gpt_unit_test.c
+++ b/tests/gpt_unit_test.c
@@ -99,8 +99,8 @@ static const struct grub_gpt_header example_primary = {
   .alternate_lba = grub_cpu_to_le64_compile_time (BACKUP_HEADER_SECTOR),
   .start = grub_cpu_to_le64_compile_time (DATA_START_SECTOR),
   .end = grub_cpu_to_le64_compile_time (DATA_END_SECTOR),
-  .guid = {0xad, 0x31, 0xc1, 0x69, 0xd6, 0x67, 0xc6, 0x46,
-	   0x93, 0xc4, 0x12, 0x4c, 0x75, 0x52, 0x56, 0xac},
+  .guid = GRUB_GPT_GUID_INIT(0x69c131ad, 0x67d6, 0x46c6,
+			     0x93, 0xc4, 0x12, 0x4c, 0x75, 0x52, 0x56, 0xac),
   .partitions = grub_cpu_to_le64_compile_time (PRIMARY_TABLE_SECTOR),
   .maxpart = grub_cpu_to_le32_compile_time (TABLE_ENTRIES),
   .partentry_size = grub_cpu_to_le32_compile_time (ENTRY_SIZE),
@@ -117,8 +117,8 @@ static const struct grub_gpt_header example_backup = {
   .alternate_lba = grub_cpu_to_le64_compile_time (PRIMARY_HEADER_SECTOR),
   .start = grub_cpu_to_le64_compile_time (DATA_START_SECTOR),
   .end = grub_cpu_to_le64_compile_time (DATA_END_SECTOR),
-  .guid = {0xad, 0x31, 0xc1, 0x69, 0xd6, 0x67, 0xc6, 0x46,
-	   0x93, 0xc4, 0x12, 0x4c, 0x75, 0x52, 0x56, 0xac},
+  .guid = GRUB_GPT_GUID_INIT(0x69c131ad, 0x67d6, 0x46c6,
+			     0x93, 0xc4, 0x12, 0x4c, 0x75, 0x52, 0x56, 0xac),
   .partitions = grub_cpu_to_le64_compile_time (BACKUP_TABLE_SECTOR),
   .maxpart = grub_cpu_to_le32_compile_time (TABLE_ENTRIES),
   .partentry_size = grub_cpu_to_le32_compile_time (ENTRY_SIZE),
@@ -326,13 +326,13 @@ header_test (void)
   grub_errno = GRUB_ERR_NONE;
 
   /* Twiddle the GUID to invalidate the CRC. */
-  primary.guid[0] = 0;
+  primary.guid.data1 = 0;
   grub_gpt_header_check (&primary, GRUB_DISK_SECTOR_BITS);
   grub_test_assert (grub_errno == GRUB_ERR_BAD_PART_TABLE,
 		    "unexpected error: %s", grub_errmsg);
   grub_errno = GRUB_ERR_NONE;
 
-  backup.guid[0] = 0;
+  backup.guid.data1 = 0;
   grub_gpt_header_check (&backup, GRUB_DISK_SECTOR_BITS);
   grub_test_assert (grub_errno == GRUB_ERR_BAD_PART_TABLE,
 		    "unexpected error: %s", grub_errmsg);