diff --git a/include/dwg.h b/include/dwg.h
index 762f5244d4..722bee14a3 100644
--- a/include/dwg.h
+++ b/include/dwg.h
@@ -9037,10 +9037,11 @@ typedef enum DWG_SECTION_TYPE_R13
   SECTION_HEADER_R13 = 0,
   SECTION_CLASSES_R13 = 1,
   SECTION_HANDLES_R13 = 2,
-  SECTION_OBJFREESPACE_R13 = 3, /* including the 2ndheader */
+  SECTION_OBJFREESPACE_R13 = 3,
   SECTION_TEMPLATE_R13 = 4,
   SECTION_AUXHEADER_R2000 = 5,
   SECTION_THUMBNAIL_R13 = 6,
+  SECTION_SECOND_HEADER_R13 = 7,
 } Dwg_Section_Type_r13;
 
 typedef enum DWG_SECTION_TYPE_R11 /* tables */
@@ -9379,7 +9380,7 @@ typedef struct _dwg_header
   BITCODE_RL summaryinfo_address; /* R2004+ */
   BITCODE_RL vbaproj_address;     /* R2004+ */
   BITCODE_RL r2004_header_address; /* R2004+ */
-  BITCODE_RL sections;            // as in the header, 5 or 6 usually
+  BITCODE_RL sections;            // as in the header, 3 .. 6 usually
   BITCODE_RL num_sections;        // as allocated, many more
   Dwg_Section *section;
   Dwg_Section_InfoHdr section_infohdr; /* R2004+ */
diff --git a/src/decode.c b/src/decode.c
index a4d8e40b43..4f9f58253c 100644
--- a/src/decode.c
+++ b/src/decode.c
@@ -333,11 +333,10 @@ decode_R13_R2000 (Bit_Chain *restrict dat, Dwg_Data *restrict dwg)
    *         1: class section
    *         2: Handles (object map)
    *         3: optional: ObjFreeSpace
-   *         -: 2ndHeader and its sentinels
    *         4: optional: Template (MEASUREMENT)
    *         5: optional: AuxHeader (no sentinels, since R13c3)
    */
-  for (j = 0; j < dwg->header.num_sections; j++)
+  for (j = 0; j < dwg->header.sections; j++)
     {
       dwg->header.section[j].number = (BITCODE_RLd)bit_read_RC (dat);
       dwg->header.section[j].address = (BITCODE_RLL)bit_read_RL (dat);
diff --git a/src/dwg.c b/src/dwg.c
index 20a793c898..376b374e89 100644
--- a/src/dwg.c
+++ b/src/dwg.c
@@ -3378,7 +3378,8 @@ dwg_sections_init (Dwg_Data *dwg)
       /* section 0: header vars
        *         1: class section
        *         2: object map (i.e. handles)
-       *         3: optional ObjFreeSpace (r13+, no sentinels) + 2ndheader (r13+, sentinels)
+       *         3: optional ObjFreeSpace (r13c3+, no sentinels)
+       *         7: 2ndheader (not a section, r13+, sentinels)
        *         4: optional: Template (MEASUREMENT)
        *         5: optional: AuxHeader (no sentinels, since R_2000b)
        *         6: optional: THUMBNAIL (not a section, but treated as one)
@@ -3386,22 +3387,27 @@ dwg_sections_init (Dwg_Data *dwg)
       if (!dwg->header.num_sections ||
           (dwg->header.from_version > R_2000 && dwg->header.version <= R_2000))
         {
-          dwg->header.num_sections = dwg->header.version < R_13c3    ? 3
-                                     : dwg->header.version < R_2000b ? 5
-                                                                     : 6;
-          if (dwg->header.num_sections == 3 && dwg->objfreespace.numnums)
-            dwg->header.num_sections = 5;
+          if (dwg->header.sections)
+            {
+              // Plus thumbnail and second header
+              dwg->header.num_sections = dwg->header.sections + 2;
+            }
+          else
+            {
+              dwg->header.num_sections = dwg->header.version < R_13c3    ? 5
+                                         : dwg->header.version < R_2000b ? 7
+                                                                         : 8;
+              if (dwg->header.num_sections == 5 && dwg->objfreespace.numnums)
+                dwg->header.num_sections = 6;
+            }
         }
       if (!dwg->header.sections ||
           (dwg->header.from_version > R_2000 && dwg->header.version <= R_2000))
-         // ODA writes zeros
-        dwg->header.sections = dwg->header.num_sections;
-      // newer DWG's have proper HEADER.sections
-      if (dwg->header.num_sections != dwg->header.sections)
-        dwg->header.num_sections = dwg->header.sections;
+        // ODA writes zeros
+        dwg->header.sections = dwg->header.num_sections - 2;
     }
   LOG_TRACE ("num_sections => " FORMAT_RL "\n", dwg->header.num_sections);
-  if (dwg->header.num_sections < 3)
+  if (dwg->header.num_sections < 5)
     {
       LOG_ERROR ("Not enough sections: " FORMAT_RL, dwg->header.num_sections);
       return DWG_ERR_INVALIDDWG;
@@ -3413,13 +3419,13 @@ dwg_sections_init (Dwg_Data *dwg)
     }
 
   if (dwg->header.section)
-    // zero-based, including THUMBNAIL
+    // zero-based, including THUMBNAIL and Second Header
     dwg->header.section = (Dwg_Section *)realloc (
         dwg->header.section,
-        sizeof (Dwg_Section) * (dwg->header.num_sections + 2));
+        sizeof (Dwg_Section) * (dwg->header.num_sections));
   else
     dwg->header.section = (Dwg_Section *)calloc (sizeof (Dwg_Section),
-                                                 dwg->header.num_sections + 2);
+                                                 dwg->header.num_sections);
   if (!dwg->header.section)
     {
       LOG_ERROR ("Out of memory");
diff --git a/src/encode.c b/src/encode.c
index 9f7bf4a80c..ce87ecf794 100644
--- a/src/encode.c
+++ b/src/encode.c
@@ -85,7 +85,7 @@ static BITCODE_BL rcount1 = 0, rcount2 = 0;
 /* section_order: A static array of section types.
    SECTION_R13_SIZE is the size and the sentinel.
  */
-#define SECTION_R13_SIZE 7U
+#define SECTION_R13_SIZE 8U
 static Dwg_Section_Type_r13 section_order[SECTION_R13_SIZE] = { 0 };
 
 #ifdef USE_TRACING
@@ -1996,7 +1996,7 @@ find_section_info_type (const Dwg_Data *restrict dwg, Dwg_Section_Type type)
   return NULL;
 }
 
-/* Ordering of r13-r2000 sections 0-6 */
+/* Ordering of r13-r2000 sections 0-7 */
 static void
 section_order_trace (const Dwg_Data *dwg,
                      const BITCODE_BL numsections,
@@ -3066,22 +3066,16 @@ encode_objects_handles (Dwg_Data *restrict dwg, Bit_Chain *restrict dat,
 }
 
 static int
-encode_objfreespace_2ndheader (Dwg_Data *restrict dwg, Bit_Chain *restrict dat)
+encode_objfreespace (Dwg_Data *restrict dwg, Bit_Chain *restrict dat)
 {
   int error = 0;
-  BITCODE_BL i;
-  size_t pvzadr;
 
   /*------------------------------------------------------------
-   * ObjFreeSpace and Second header - r13-r2000 only.
-   * Note: partially also since r2004.
+   * ObjFreeSpace - r13c3-r2000 only.
    */
   if (dwg->header.version >= R_13 && dwg->header.version < R_2004
       && dwg->header.num_sections >= 3)
     {
-      struct _dwg_secondheader *_obj = &dwg->secondheader;
-      Dwg_Object *obj = NULL;
-
       assert (dat->byte);
       dwg->header.section[SECTION_OBJFREESPACE_R13].number = 3;
       if (dwg->objfreespace.numnums)
@@ -3094,6 +3088,26 @@ encode_objfreespace_2ndheader (Dwg_Data *restrict dwg, Bit_Chain *restrict dat)
           LOG_INFO ("=======> ObjFreeSpace 3 (end): %4u\n",
                     (unsigned)dat->byte);
         }
+    }
+
+  return error;
+}
+
+static int
+encode_2ndheader (Dwg_Data *restrict dwg, Bit_Chain *restrict dat)
+{
+  int error = 0;
+  BITCODE_BL i;
+  size_t pvzadr;
+
+  /*------------------------------------------------------------
+   * Second Header - r13-r2000 only.
+   */
+  if (dwg->header.version >= R_13 && dwg->header.version < R_2004
+      && dwg->header.num_sections >= 3)
+    {
+      struct _dwg_secondheader *_obj = &dwg->secondheader;
+      Dwg_Object *obj = NULL;
 
       LOG_INFO ("\n=======> Second Header: %4zu\n", dat->byte + 16);
       write_sentinel (dat, DWG_SENTINEL_2NDHEADER_BEGIN);
@@ -3715,15 +3729,15 @@ dwg_encode (Dwg_Data *restrict dwg, Bit_Chain *restrict dat)
                   THUMBNAIL
      *         2: Handles
      *         3: ObjFreeSpace (r13c3+, optional)
-                  + 2NDHEADER (r13-r2000)
+     *         7: 2NDHEADER (r13-r2000, not a section)
      *         4: Template (r14-r2000, optional)
      *         5: AuxHeader (r2000, no sentinels)
      *         6: THUMBNAIL (r13c3+, not a section)
      */
     
-    /* Usually 3-5, max 6 */
+    /* Usually 5-7, max 8 */
     if (!dwg->header.num_sections
-        || (dat->from_version >= R_2004 && dwg->header.num_sections > 6))
+        || (dat->from_version >= R_2004 && dwg->header.num_sections > 8))
       {
         if (dwg->header.version <= R_2000)
           {
@@ -3732,11 +3746,11 @@ dwg_encode (Dwg_Data *restrict dwg, Bit_Chain *restrict dat)
             else
               dwg->header.num_sections
                   = dwg->auxheader.dwg_version && dwg->header.version == R_2000
-                        ? 6
-                        : 5;
+                        ? 7
+                        : 6;
           }
         else
-          dwg->header.num_sections = 6;
+          dwg->header.num_sections = 7;
         // minimal DXF:
         // if (dwg->opts & (DWG_OPTS_INDXF | DWG_OPTS_MINIMAL)
         //    && (!dwg->header_vars.HANDSEED ||
@@ -3766,19 +3780,23 @@ dwg_encode (Dwg_Data *restrict dwg, Bit_Chain *restrict dat)
       if (dwg->header.sections > 3)
         {
           section_order[3] = SECTION_OBJFREESPACE_R13;
-          section_order[4] = SECTION_TEMPLATE_R13;
+          section_order[4] = SECTION_SECOND_HEADER_R13;
+          section_order[5] = SECTION_TEMPLATE_R13;
           if (dwg->header.sections > 5)
             {
-              section_order[5] = SECTION_AUXHEADER_R2000;
-              section_order[6] = SECTION_THUMBNAIL_R13;
+              section_order[6] = SECTION_AUXHEADER_R2000;
+              section_order[7] = SECTION_THUMBNAIL_R13;
             }
           else
             {
-              section_order[5] = SECTION_THUMBNAIL_R13;
+              section_order[6] = SECTION_THUMBNAIL_R13;
             }
         }
       else
-        section_order[3] = SECTION_THUMBNAIL_R13;
+        {
+          section_order[3] = SECTION_THUMBNAIL_R13;
+          section_order[4] = SECTION_SECOND_HEADER_R13;
+        }
 
       if (DWG_LOGLEVEL >= DWG_LOGLEVEL_TRACE)
         section_order_trace (dwg, dwg->header.num_sections,
@@ -3894,20 +3912,10 @@ dwg_encode (Dwg_Data *restrict dwg, Bit_Chain *restrict dat)
                 error |= encode_objects_handles (dwg, dat, (Bit_Chain **)&sec_dat);
                 break;
               case SECTION_OBJFREESPACE_R13:
-                {
-                  int err1;
-                  pvzadr = dat->byte;
-                  err1 = encode_objfreespace_2ndheader (dwg, dat);
-                  /*
-                  if (err1 & 1)
-                    {
-                      LOG_TRACE ("2ndheader size changed, rewrite it\n")
-                      dat->byte = pvzadr;
-                      err1 = encode_objfreespace_2ndheader (dwg, dat);
-                    }
-                  */
-                  error |= err1;
-                }
+                error |= encode_objfreespace (dwg, dat);
+                break;
+              case SECTION_SECOND_HEADER_R13:
+                error |= encode_2ndheader (dwg, dat);
                 break;
               case SECTION_TEMPLATE_R13:
                 error |= encode_template (dwg, dat);