Ignore the AlternateLBA field in the GPT headers.

src/platform/vboot_reference/utility/cgpt/cgpt_options.c

Index: src/platform/vboot_reference/utility/cgpt/cgpt_options.c
diff --git a/src/platform/vboot_reference/utility/cgpt/cgpt_options.c b/src/platform/vboot_reference/utility/cgpt/cgpt_options.c
index c119ac9f49a8bebf16de39efb1172f6a0a869f4c..b434eeaf3650325f2553cf6221e1f0546d0646ab 100644
--- a/src/platform/vboot_reference/utility/cgpt/cgpt_options.c
+++ b/src/platform/vboot_reference/utility/cgpt/cgpt_options.c
@@ -125,27 +125,10 @@ int HandleOptions(const int argc,
 int OpenDriveInLastArgument(const int argc,
                             char *const *argv,
                             struct drive *drive) {
-  /* Then, we need a non-option argument. */
-  if (optind == (argc - 1)) {
-    char *path, drive_path[256];
-    path = argv[optind];
-    switch (path[0]) {
-      case '.':
-      case '/':
-        snprintf(drive_path, sizeof(drive_path), "%s", path);
-        break;
-      default:
-        snprintf(drive_path, sizeof(drive_path), "/dev/%s", path);
-        break;
-    }
-    if (CGPT_OK != DriveOpen(drive_path, drive)) {
-      printf("[ERROR] DriveOpen(%s) error!\n", drive_path);
-      return CGPT_FAILED;
-    }
-  } else {
+  if (optind != (argc - 1)) {
     printf("[ERROR] One (and only one) non-option argument is required.\n");
     return CGPT_FAILED;
   }
 
-  return CGPT_OK;
+  return DriveOpen(argv[optind], drive);
 }