This fixes the EFI BIOS boot problems introduced with cgpt.

cgpt/cmd_create.c

 // Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cgpt.h"
 
 #include <getopt.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ skipping 70 matching lines @@
                          GPT_MODIFIED_HEADER2 | GPT_MODIFIED_ENTRIES2);
 
   // Initialize a blank set
   if (!zap)
   {
     GptHeader *h = (GptHeader *)drive.gpt.primary_header;
     memcpy(h->signature, GPT_HEADER_SIGNATURE, GPT_HEADER_SIGNATURE_SIZE);
     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);
     h->entries_lba = 2;
     h->number_of_entries = 128;
     h->size_of_entry = sizeof(GptEntry);
 
     // Copy to secondary
     RepairHeader(&drive.gpt, MASK_PRIMARY);
 
     UpdateCrc(&drive.gpt);
   }
 
   // Write it all out
   return DriveClose(&drive, 1);
 }