diff --git a/macbuild/Resources/KLayoutDMG-Back.logoist b/macbuild/Resources/KLayoutDMG-Back.logoist
index a154272e8..4f87f0910 100644
Binary files a/macbuild/Resources/KLayoutDMG-Back.logoist and b/macbuild/Resources/KLayoutDMG-Back.logoist differ
diff --git a/macbuild/Resources/KLayoutDMG-Back.png b/macbuild/Resources/KLayoutDMG-Back.png
index 1e644ee46..4a2465f84 100644
Binary files a/macbuild/Resources/KLayoutDMG-Back.png and b/macbuild/Resources/KLayoutDMG-Back.png differ
diff --git a/macbuild/Resources/script-bundle-B.zip b/macbuild/Resources/script-bundle-B.zip
index 25d7a5b89..130d6de99 100644
Binary files a/macbuild/Resources/script-bundle-B.zip and b/macbuild/Resources/script-bundle-B.zip differ
diff --git a/macbuild/build4mac.py b/macbuild/build4mac.py
index 6148357b1..7ee07758c 100755
--- a/macbuild/build4mac.py
+++ b/macbuild/build4mac.py
@@ -34,7 +34,7 @@ def Get_Default_Config():
     Usage  = "\n"
     Usage += "---------------------------------------------------------------------------------------------------------\n"
     Usage += "<< Usage of 'build4mac.py' >>\n"
-    Usage += "       for building KLayout 0.26.11 or later on different Apple Mac OSX platforms.\n"
+    Usage += "       for building KLayout 0.26.12 or later on different Apple Mac OSX / macOS platforms.\n"
     Usage += "\n"
     Usage += "$ [python] ./build4mac.py \n"
     Usage += "   option & argument    : descriptions (refer to 'macbuild/build4mac_env.py' for details)| default value\n"
@@ -55,11 +55,11 @@ def Get_Default_Config():
     Usage += "                        :    Sys: use OS-bundled Python 2.7 [ElCapitan -- BigSur]        | \n"
     Usage += "                        :   MP38: use Python 3.8 from MacPorts                           | \n"
     Usage += "                        :   HB38: use Python 3.8 from Homebrew                           | \n"
-    Usage += "                        :   Ana3: use Python 3.7 from Anaconda3                          | \n"
+    Usage += "                        :   Ana3: use Python 3.8 from Anaconda3                          | \n"
     Usage += "                        : HBAuto: use the latest Python 3.x auto-detected from Homebrew  | \n"
     Usage += "   [-n|--noqtbinding]   : don't create Qt bindings for ruby scripts                      | disabled \n"
     Usage += "   [-u|--noqtuitools]   : don't include uitools in Qt binding                            | disabled \n"
-    Usage += "   [-m|--make <option>] : option passed to 'make'                                        | '-j4' \n"
+    Usage += "   [-m|--make <option>] : option passed to 'make'                                        | '--jobs=4' \n"
     Usage += "   [-d|--debug]         : enable debug mode build                                        | disabled \n"
     Usage += "   [-c|--checkcom]      : check command-line and exit without building                   | disabled \n"
     Usage += "   [-y|--deploy]        : deploy executables and dylibs including Qt's Frameworks        | disabled \n"
@@ -107,10 +107,15 @@ def Get_Default_Config():
         sys.exit(1)
 
     if not Machine == "x86_64":
-        print("")
-        print( "!!! Sorry. Only x86_64 architecture machine is supported but found <%s>" % Machine, file=sys.stderr )
-        print(Usage)
-        sys.exit(1)
+        if Machine == "arm64" and Platform == "BigSur": # with an Apple Silicon Chip
+            print("")
+            print( "### Your Mac equips an Apple Silicon Chip ###" )
+            print("")
+        else:
+            print("")
+            print( "!!! Sorry. Only x86_64/arm64 architecture machine is supported but found <%s>" % Machine, file=sys.stderr )
+            print(Usage)
+            sys.exit(1)
 
     # Set the default modules
     ModuleQt = "Qt5MacPorts"
@@ -139,7 +144,7 @@ def Get_Default_Config():
     NonOSStdLang  = False
     NoQtBindings  = False
     NoQtUiTools   = False
-    MakeOptions   = "-j4"
+    MakeOptions   = "--jobs=4"
     DebugMode     = False
     CheckComOnly  = False
     DeploymentF   = False
@@ -279,7 +284,7 @@ def Parse_CLI_Args(config):
                     type_python    = "sys",
                     no_qt_binding  = False,
                     no_qt_uitools  = False,
-                    make_option    = "-j4",
+                    make_option    = "--jobs=4",
                     debug_build    = False,
                     check_command  = False,
                     deploy_full    = False,
diff --git a/macbuild/build4mac_env.py b/macbuild/build4mac_env.py
index 726380184..726e90af4 100755
--- a/macbuild/build4mac_env.py
+++ b/macbuild/build4mac_env.py
@@ -12,14 +12,25 @@
 #===============================================================================
 import os
 import glob
+import platform
 
-#-----------------------------------------------------
+#---------------------------------------------------------------------------------------------------
 # [0] Xcode's tools
-#-----------------------------------------------------
+#       and
+#     Default Homebrew root
+#       Ref. https://github.com/Homebrew/brew/blob/master/docs/Installation.md#alternative-installs
+#---------------------------------------------------------------------------------------------------
 XcodeToolChain = { 'nameID': '/usr/bin/install_name_tool -id ',
                    'nameCH': '/usr/bin/install_name_tool -change '
                  }
 
+(System, Node, Release, MacVersion, Machine, Processor) = platform.uname()
+if Machine == "arm64": # Apple Silicon!
+  DefaultHomebrewRoot = '/opt/homebrew'
+else:
+  DefaultHomebrewRoot = '/usr/local'
+del System, Node, Release, MacVersion, Machine, Processor
+
 #-----------------------------------------------------
 # [1] Qt
 #-----------------------------------------------------
@@ -38,8 +49,8 @@ Qt5MacPorts = { 'qmake' : '/opt/local/libexec/qt5/bin/qmake',
 # Qt5 from Homebrew (https://brew.sh/)
 #   install with 'brew install qt'
 # [Key Type Name] = 'Qt5Brew'
-Qt5Brew = { 'qmake' : '/usr/local/opt/qt/bin/qmake',
-            'deploy': '/usr/local/opt/qt/bin/macdeployqt'
+Qt5Brew = { 'qmake' : '%s/opt/qt/bin/qmake' % DefaultHomebrewRoot,
+            'deploy': '%s/opt/qt/bin/macdeployqt' %DefaultHomebrewRoot
           }
 
 # Qt5 bundled with anaconda3 installed under /Applications/anaconda3/
@@ -145,7 +156,7 @@ Ruby27MacPorts  = { 'exe': '/opt/local/bin/ruby2.7',
 # Ruby 2.7 from Homebrew *+*+*+ EXPERIMENTAL *+*+*+
 #   install with 'brew install ruby'
 # [Key Type Name] = 'HB27'
-HBRuby27Path    = '/usr/local/opt/ruby'
+HBRuby27Path    = '%s/opt/ruby' % DefaultHomebrewRoot
 Ruby27Brew      = { 'exe': '%s/bin/ruby' % HBRuby27Path,
                     'inc': '%s/include/ruby-2.7.0' % HBRuby27Path,
                     'lib': '%s/lib/libruby.2.7.dylib' % HBRuby27Path
@@ -247,7 +258,7 @@ Python38MacPorts= { 'exe': '/opt/local/Library/Frameworks/Python.framework/Versi
 # Python 3.8 from Homebrew *+*+*+ EXPERIMENTAL *+*+*+
 #   install with 'brew install python'
 # [Key Type Name] = 'HB38'
-HBPython38FrameworkPath = '/usr/local/opt/python@3.8/Frameworks/Python.framework'
+HBPython38FrameworkPath = '%s/opt/python@3.8/Frameworks/Python.framework' % DefaultHomebrewRoot
 Python38Brew    = { 'exe': '%s/Versions/3.8/bin/python3.8' % HBPython38FrameworkPath,
                     'inc': '%s/Versions/3.8/include/python3.8' % HBPython38FrameworkPath,
                     'lib': '%s/Versions/3.8/lib/libpython3.8.dylib' % HBPython38FrameworkPath
@@ -270,7 +281,7 @@ PythonAnaconda3 = { 'exe': '/Applications/anaconda3/bin/python3.8',
 HBPythonAutoFrameworkPath = ""
 HBPythonAutoVersion       = ""
 try:
-    HBPythonAutoFrameworkPath = glob.glob( "/usr/local/opt/python*/Frameworks/Python.framework" )[-1]
+    HBPythonAutoFrameworkPath = glob.glob( "%s/opt/python*/Frameworks/Python.framework" % DefaultHomebrewRoot )[-1]
     # expand 3* into HBPythonAutoVersion, there should be only one, but I am taking no chances.
     HBAutoFrameworkVersionPath, HBPythonAutoVersion = os.path.split( glob.glob( "%s/Versions/3*" % HBPythonAutoFrameworkPath )[0] )
     PythonAutoBrew  = { 'exe': '%s/%s/bin/python%s' % ( HBAutoFrameworkVersionPath, HBPythonAutoVersion, HBPythonAutoVersion ),
diff --git a/macbuild/makeDMG4mac.py b/macbuild/makeDMG4mac.py
index a8b795c93..4fb5b2076 100755
--- a/macbuild/makeDMG4mac.py
+++ b/macbuild/makeDMG4mac.py
@@ -77,7 +77,7 @@ def SetGlobals():
     Usage  = "\n"
     Usage += "--------------------------------------------------------------------------------------------------------\n"
     Usage += "<< Usage of 'makeDMG4mac.py' >>\n"
-    Usage += "       for making a DMG file of KLayout 0.26.1 or later on different Apple Mac OSX platforms.\n"
+    Usage += "       for making a DMG file of KLayout 0.26.12 or later on different Apple Mac OSX / macOS platforms.\n"
     Usage += "\n"
     Usage += "$ [python] ./makeDMG4mac.py \n"
     Usage += "   option & argument    : descriptions                                               | default value\n"
@@ -89,8 +89,8 @@ def SetGlobals():
     Usage += "                        :   <-c|--clean> and <-m|--make> are mutually exclusive      | \n"
     Usage += "   [-b|--bundle <name>] : forcibly use this bundle name in the DMG                   | '' \n"
     Usage += "   [-s|--serial <num>]  : DMG serial number                                          | 1 \n"
-    Usage += "   <-u|--unsafe>        : Ignores a few checks (use with caution)                    | disabled \n"
-    Usage += "   <-t|--targetdmg>     : Specify output .dmg filename                               | chosen by script \n"
+    Usage += "   [-u|--unsafe]        : Ignores a few checks (use with caution)                    | disabled \n"
+    Usage += "   [-t|--targetdmg]     : Specify output .dmg filename                               | chosen by script \n"
     Usage += "   [-?|--?]             : print this usage and exit                                  | disabled \n"
     Usage += "-------------------------------------------------------------------------------------+------------------\n"
 
@@ -133,10 +133,15 @@ def SetGlobals():
         sys.exit(1)
 
     if not Machine == "x86_64":
-        print("")
-        print( "!!! Sorry. Only x86_64 architecture machine is supported but found <%s>" % Machine, file=sys.stderr )
-        print(Usage)
-        sys.exit(1)
+        if Machine == "arm64" and Platform == "BigSur": # with an Apple Silicon Chip
+            print("")
+            print( "### Your Mac equips an Apple Silicon Chip ###" )
+            print("")
+        else:
+            print("")
+            print( "!!! Sorry. Only x86_64/arm64 architecture machine is supported but found <%s>" % Machine, file=sys.stderr )
+            print(Usage)
+            sys.exit(1)
 
     PkgDir            = ""
     UnsafePkg         = False
@@ -358,6 +363,7 @@ def ParseCommandLineArguments():
     global KLVersion
     global OccupiedDS
     global TargetDMG
+    global Machine
 
     p = optparse.OptionParser( usage=Usage )
     p.add_option( '-p', '--pkg',
@@ -448,6 +454,8 @@ def ParseCommandLineArguments():
     else:
         TargetDMG = "%s-klayout-%s-%s-%s-%d-%s-%s.dmg" \
                         % (PackagePrefix, KLVersion, GenOSName, Platform, DMGSerialNum, QtIdentification, RubyPythonID)
+        if Machine == "arm64": # with an Apple Silicon Chip
+            TargetDMG = Machine + TargetDMG
     return
 
 #------------------------------------------------------------------------------
diff --git a/macbuild/nightlyBuild.py b/macbuild/nightlyBuild.py
index 2d448dd3c..07d0a9518 100755
--- a/macbuild/nightlyBuild.py
+++ b/macbuild/nightlyBuild.py
@@ -199,7 +199,7 @@ def Parse_CommandLine_Arguments():
     Usage += "          (3) $ ./nightlyBuild.py  --test                                  | \n"
     Usage += "          (4) $ ./nightlyBuild.py  --check (confirm the QA Test results)   | \n"
     Usage += "          (5) $ ./nightlyBuild.py  --makedmg  1                            | \n"
-    Usage += "          (6) $ ./nightlyBuild.py  --upload  '0.26.10'                     | \n"
+    Usage += "          (6) $ ./nightlyBuild.py  --upload  '0.26.12'                     | \n"
     Usage += "          (7) $ ./nightlyBuild.py  --cleandmg 1                            | \n"
     Usage += "---------------------------------------------------------------------------+----------------\n"