Successful partitions are never marked bad by cgptlib.

firmware/lib/cgptlib/cgptlib.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 "cgptlib.h"
 #include "cgptlib_internal.h"
 #include "crc32.h"
 #include "gpt.h"
 #include "utility.h"
@@ skipping 111 matching lines @@
       tries = GetEntryTries(e);
       if (tries > 1) {
         /* Still have tries left */
         SetEntryTries(e, tries - 1);
         break;
       }
       /* Out of tries, so drop through and mark partition bad. */
     }
     case GPT_UPDATE_ENTRY_BAD: {
       /* Giving up on this partition entirely. */
-      e->attrs.fields.gpt_att = previous_attr & ~(
-          CGPT_ATTRIBUTE_SUCCESSFUL_MASK |
-          CGPT_ATTRIBUTE_TRIES_MASK |
-          CGPT_ATTRIBUTE_PRIORITY_MASK);
+      if (!GetEntrySuccessful(e)) {
+        /* Only clear tries and priority if the successful bit is not set. */
+        e->attrs.fields.gpt_att = previous_attr & ~(
+            CGPT_ATTRIBUTE_SUCCESSFUL_MASK |

[Bill Richardson, 2010/09/07 17:24:53]

You don't need to explicitly clear the Attribute bit, since it's already cleared
or you wouldn't be here.

+            CGPT_ATTRIBUTE_TRIES_MASK |
+            CGPT_ATTRIBUTE_PRIORITY_MASK);
+      }
       break;
     }
     default:
       return GPT_ERROR_INVALID_UPDATE_TYPE;
   }
 
   /* If no change to attributes, we're done */
   if (e->attrs.fields.gpt_att == previous_attr)
     return GPT_SUCCESS;
 
   /* Update the CRCs */
   header->entries_crc32 = Crc32((const uint8_t *)entries,
                                 header->size_of_entry *
                                 header->number_of_entries);
   header->header_crc32 = HeaderCrc(header);
   gpt->modified |= GPT_MODIFIED_HEADER1 | GPT_MODIFIED_ENTRIES1;
 
   /* Use the repair function to update the other copy of the GPT.
    * This is a tad inefficient, but is much faster than the disk I/O
    * to update the GPT on disk so it doesn't matter. */
   gpt->valid_headers = MASK_PRIMARY;
   gpt->valid_entries = MASK_PRIMARY;
   GptRepair(gpt);
 
   return GPT_SUCCESS;
 }