diff --git a/cgpt/cmd_create.c b/cgpt/cmd_create.c
index 4e6eb65..1680370 100644
--- a/cgpt/cmd_create.c
+++ b/cgpt/cmd_create.c
@@ -88,6 +88,7 @@
     h->revision = GPT_HEADER_REVISION;
     h->size = sizeof(GptHeader);
     h->my_lba = 1;
+    h->alternate_lba = drive.gpt.drive_sectors - 1;
     h->first_usable_lba = 1 + 1 + GPT_ENTRIES_SECTORS;
     h->last_usable_lba = drive.gpt.drive_sectors - 1 - GPT_ENTRIES_SECTORS - 1;
     uuid_generate((uint8_t *)&h->disk_uuid);
diff --git a/cgpt/cmd_show.c b/cgpt/cmd_show.c
index 9f52cb1..9146149 100644
--- a/cgpt/cmd_show.c
+++ b/cgpt/cmd_show.c
@@ -95,6 +95,7 @@
   printf("%sSize: %d\n", indent, header->size);
   printf("%sHeader CRC: 0x%08x\n", indent, header->header_crc32);
   printf("%sMy LBA: %lld\n", indent, (long long)header->my_lba);
+  printf("%sAlternate LBA: %lld\n", indent, (long long)header->alternate_lba);
   printf("%sFirst LBA: %lld\n", indent, (long long)header->first_usable_lba);
   printf("%sLast LBA: %lld\n", indent, (long long)header->last_usable_lba);
 
diff --git a/vboot_firmware/lib/cgptlib/include/gpt.h b/vboot_firmware/lib/cgptlib/include/gpt.h
index 7a1d576..4ba016c 100644
--- a/vboot_firmware/lib/cgptlib/include/gpt.h
+++ b/vboot_firmware/lib/cgptlib/include/gpt.h
@@ -79,13 +79,12 @@
   uint64_t first_usable_lba;
   uint64_t last_usable_lba;
   Guid disk_uuid;
-
   uint64_t entries_lba;
   uint32_t number_of_entries;
   uint32_t size_of_entry;
   uint32_t entries_crc32;
   uint8_t reserved_padding[];           /* entire sector reserved for header */
-} GptHeader;
+} __attribute__((packed)) GptHeader;
 
 /* GPT partition entry defines the starting and ending LBAs of a partition.
  * It also contains the unique GUID, type, and attribute bits.
@@ -100,6 +99,6 @@
   uint64_t attributes;
   uint16_t name[36];                    /* UTF-16 encoded partition name */
   uint8_t reserved[];                   /* nothing, really */
-} GptEntry;
+} __attribute__((packed)) GptEntry;
 
 #endif  /* VBOOT_REFERENCE_CGPTLIB_GPT_H_ */