diff --git a/Readme.md b/Readme.md
index 81fd9fd9d..f2ea4b094 100644
--- a/Readme.md
+++ b/Readme.md
@@ -66,9 +66,9 @@ Open Asset Import Library is implemented in C++. The directory structure looks l
 
 The source code is organized in the following way:
 
-	code/Common		The base implementation for importers and the infrastructure
-	code/PostProcessing	The post-processing steps
-	code/<FormatName>	Implementation for import and export for the format
+	code/Common			The base implementation for importers and the infrastructure
+	code/PostProcessing		The post-processing steps
+	code/AssetLib/<FormatName>	Implementation for import and export for the format
 
 ### Where to get help ###
 For more information, visit [our website](http://assimp.org/). Or check out the `./doc`- folder, which contains the official documentation in HTML format.
diff --git a/code/AssetLib/Blender/BlenderDNA.cpp b/code/AssetLib/Blender/BlenderDNA.cpp
index 4dcb3d654..c58041771 100644
--- a/code/AssetLib/Blender/BlenderDNA.cpp
+++ b/code/AssetLib/Blender/BlenderDNA.cpp
@@ -200,7 +200,7 @@ void DNAParser::Parse() {
 
     ASSIMP_LOG_DEBUG_F("BlenderDNA: Got ", dna.structures.size(), " structures with totally ", fields, " fields");
 
-#ifdef ASSIMP_BUILD_BLENDER_DEBUG
+#if ASSIMP_BUILD_BLENDER_DEBUG_DNA
     dna.DumpToFile();
 #endif
 
@@ -208,7 +208,7 @@ void DNAParser::Parse() {
     dna.RegisterConverters();
 }
 
-#ifdef ASSIMP_BUILD_BLENDER_DEBUG
+#if ASSIMP_BUILD_BLENDER_DEBUG_DNA
 
 #include <fstream>
 // ------------------------------------------------------------------------------------------------
@@ -237,7 +237,7 @@ void DNA ::DumpToFile() {
 
     ASSIMP_LOG_INFO("BlenderDNA: Dumped dna to dna.txt");
 }
-#endif
+#endif // ASSIMP_BUILD_BLENDER_DEBUG_DNA
 
 // ------------------------------------------------------------------------------------------------
 /*static*/ void DNA ::ExtractArraySize(
diff --git a/code/AssetLib/Blender/BlenderDNA.h b/code/AssetLib/Blender/BlenderDNA.h
index 090d1be04..f566554b8 100644
--- a/code/AssetLib/Blender/BlenderDNA.h
+++ b/code/AssetLib/Blender/BlenderDNA.h
@@ -59,6 +59,13 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #define ASSIMP_BUILD_BLENDER_DEBUG
 #endif
 
+// set this to non-zero to dump BlenderDNA stuff to dna.txt.
+// you could set it on the assimp build command line too without touching it here.
+// !!! please make sure this is set to 0 in the repo !!!
+#ifndef ASSIMP_BUILD_BLENDER_DEBUG_DNA
+#define ASSIMP_BUILD_BLENDER_DEBUG_DNA 0
+#endif
+
 // #define ASSIMP_BUILD_BLENDER_NO_STATS
 
 namespace Assimp {
@@ -495,7 +502,7 @@ public:
             const Structure &structure,
             const FileDatabase &db) const;
 
-#ifdef ASSIMP_BUILD_BLENDER_DEBUG
+#if ASSIMP_BUILD_BLENDER_DEBUG_DNA
     // --------------------------------------------------------
     /** Dump the DNA to a text file. This is for debugging purposes.
      *  The output file is `dna.txt` in the current working folder*/
diff --git a/include/assimp/Bitmap.h b/include/assimp/Bitmap.h
index d56bb4c73..e4ce194d9 100644
--- a/include/assimp/Bitmap.h
+++ b/include/assimp/Bitmap.h
@@ -75,13 +75,12 @@ protected:
         uint32_t offset;
 
         // We define the struct size because sizeof(Header) might return a wrong result because of structure padding.
-        // Moreover, we must use this ugly and error prone syntax because Visual Studio neither support constexpr or sizeof(name_of_field).
-        static const std::size_t header_size =
-            sizeof(uint16_t) + // type
-            sizeof(uint32_t) + // size
-            sizeof(uint16_t) + // reserved1
-            sizeof(uint16_t) + // reserved2
-            sizeof(uint32_t);  // offset
+        static constexpr std::size_t header_size =
+            sizeof(type) +
+            sizeof(size) +
+            sizeof(reserved1) +
+            sizeof(reserved2) +
+            sizeof(offset);
     };
 
     struct DIB {
@@ -98,22 +97,21 @@ protected:
         uint32_t nb_important_colors;
 
         // We define the struct size because sizeof(DIB) might return a wrong result because of structure padding.
-        // Moreover, we must use this ugly and error prone syntax because Visual Studio neither support constexpr or sizeof(name_of_field).
-        static const std::size_t dib_size =
-            sizeof(uint32_t) + // size
-            sizeof(int32_t) +  // width
-            sizeof(int32_t) +  // height
-            sizeof(uint16_t) + // planes
-            sizeof(uint16_t) + // bits_per_pixel
-            sizeof(uint32_t) + // compression
-            sizeof(uint32_t) + // image_size
-            sizeof(int32_t) +  // x_resolution
-            sizeof(int32_t) +  // y_resolution
-            sizeof(uint32_t) + // nb_colors
-            sizeof(uint32_t);  // nb_important_colors
+        static constexpr std::size_t dib_size =
+            sizeof(size) +
+            sizeof(width) +
+            sizeof(height) +
+            sizeof(planes) +
+            sizeof(bits_per_pixel) +
+            sizeof(compression) +
+            sizeof(image_size) +
+            sizeof(x_resolution) +
+            sizeof(y_resolution) +
+            sizeof(nb_colors) +
+            sizeof(nb_important_colors);
     };
 
-    static const std::size_t mBytesPerPixel = 4;
+    static constexpr std::size_t mBytesPerPixel = 4;
 
 public:
     static void Save(aiTexture* texture, IOStream* file);
diff --git a/port/PyAssimp/pyassimp/helper.py b/port/PyAssimp/pyassimp/helper.py
index 5c1aca827..7a4b2bdcb 100644
--- a/port/PyAssimp/pyassimp/helper.py
+++ b/port/PyAssimp/pyassimp/helper.py
@@ -27,6 +27,7 @@ if os.name=='posix':
     additional_dirs.append('./')
     additional_dirs.append('/usr/lib/')
     additional_dirs.append('/usr/lib/x86_64-linux-gnu/')
+    additional_dirs.append('/usr/lib/aarch64-linux-gnu/')
     additional_dirs.append('/usr/local/lib/')
 
     if 'LD_LIBRARY_PATH' in os.environ: