diff --git a/code_snippets/chapter12/chapter12_07-001_derivative.cpp b/code_snippets/chapter12/chapter12_07-001_derivative.cpp
index 72407e651..dd8ad2b6a 100644
--- a/code_snippets/chapter12/chapter12_07-001_derivative.cpp
+++ b/code_snippets/chapter12/chapter12_07-001_derivative.cpp
@@ -1,5 +1,5 @@
 ///////////////////////////////////////////////////////////////////////////////
-//  Copyright Christopher Kormanyos 2017 - 2025.
+//  Copyright Christopher Kormanyos 2017 - 2026.
 //  Distributed under the Boost Software License,
 //  Version 1.0. (See accompanying file LICENSE_1_0.txt
 //  or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -13,13 +13,15 @@
 #include <iomanip>
 #include <iostream>
 #include <limits>
+#include <numbers>
 #include <sstream>
 
 template<typename ValueType,
          typename FunctionType>
-auto derivative(const ValueType x,
-                const ValueType dx,
-                FunctionType function) -> ValueType
+constexpr auto derivative(ValueType x,
+                          ValueType dx,
+                          FunctionType function)
+  -> ValueType
 {
   using value_type = ValueType;
 
@@ -43,13 +45,13 @@ auto derivative(const ValueType x,
   return ((fifteen_m1 - six_m2) + m3) / ten_dx1;
 }
 
-const auto x = static_cast<float>(std::numbers::pi_v<float> / static_cast<float>(3.0L));
+constexpr float xval { static_cast<float>(std::numbers::pi_v<float> / static_cast<float>(3.0L)) };
 
 // Should be very near 0.5.
 const auto y =
-  derivative(x,
-             static_cast<float>(0.01L),
-             [](const float& x) -> float
+  derivative(xval,
+             0.01F,
+             [](float x) -> float
              {
                return std::sin(x);
              });
@@ -61,7 +63,7 @@ auto main() -> int
   std::stringstream strm { };
 
   // 0.500003
-  strm << std::setprecision(std::numeric_limits<float>::digits10) << y << '\n';
+  strm << std::setprecision(std::numeric_limits<float>::digits10) << std::fixed << y << '\n';
 
   using std::fabs;
 
diff --git a/code_snippets/chapter12/chapter12_07-002_deriv_quadratic.cpp b/code_snippets/chapter12/chapter12_07-002_deriv_quadratic.cpp
index 47cb2bcd0..5d9b6b765 100644
--- a/code_snippets/chapter12/chapter12_07-002_deriv_quadratic.cpp
+++ b/code_snippets/chapter12/chapter12_07-002_deriv_quadratic.cpp
@@ -1,5 +1,5 @@
 ///////////////////////////////////////////////////////////////////////////////
-//  Copyright Christopher Kormanyos 2017 - 2025.
+//  Copyright Christopher Kormanyos 2017 - 2026.
 //  Distributed under the Boost Software License,
 //  Version 1.0. (See accompanying file LICENSE_1_0.txt
 //  or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -15,9 +15,10 @@
 
 template<typename ValueType,
          typename FunctionType>
-auto derivative(const ValueType x,
-                const ValueType dx,
-                FunctionType function) -> ValueType
+constexpr auto derivative(const ValueType x,
+                          const ValueType dx,
+                          FunctionType function)
+  -> ValueType
 {
   using value_type = ValueType;
 
@@ -49,25 +50,22 @@ class quadratic
   const T b;
   const T c;
 
-  quadratic(const T& a_,
-            const T& b_,
-            const T& c_) : a(a_),
-                           b(b_),
-                           c(c_) { }
+ explicit constexpr quadratic(T a_, T b_, T c_)
+    : a(a_), b(b_), c(c_) { }
 
-  auto operator()(const T& x) const -> T
+  constexpr auto operator()(T x) const -> T
   {
     return ((a * x + b) * x) + c;
   }
 };
 
-const float x { 0.5F };
+constexpr float xval { 0.5F };
 
 // Should be very near 4.6.
-const float y =
-  derivative(x,
+constexpr float y =
+  derivative(xval,
              0.01F,
-             quadratic<float>(1.2F, 3.4F, 5.6F));
+             quadratic(1.2F, 3.4F, 5.6F));
 
 auto main() -> int;
 
@@ -75,8 +73,8 @@ auto main() -> int
 {
   std::stringstream strm { };
 
-  // 4.6
-  strm << std::setprecision(std::numeric_limits<float>::digits10) << y << '\n';
+  // 4.600001
+  strm << std::setprecision(std::numeric_limits<float>::digits10) << std::fixed << y << '\n';
 
   using std::fabs;
 
diff --git a/ref_app/tools/AVR/avrdude/avrdude-v8.0-windows-x64/11_07a.bat b/ref_app/tools/AVR/avrdude/avrdude-v8.0-windows-x64/11_07a.bat
new file mode 100644
index 000000000..73183b2cd
--- /dev/null
+++ b/ref_app/tools/AVR/avrdude/avrdude-v8.0-windows-x64/11_07a.bat
@@ -0,0 +1,28 @@
+rem ///////////////////////////////////////////////////////////////////////////////
+rem //  Copyright Christopher Kormanyos 2007 - 2025.
+rem //  Distributed under the Boost Software License,
+rem //  Version 1.0. (See accompanying file LICENSE_1_0.txt
+rem //  or copy at http://www.boost.org/LICENSE_1_0.txt)
+rem //
+
+echo off
+
+set AVRDUDE=.\avrdude.exe
+
+set HEX=../../../../../examples/chapter11_07a/bin/chapter11_07a.hex
+
+
+rem Erase the chip.
+echo "Erase the chip."
+%AVRDUDE% -c avrisp2 -p m328p -P usb -e
+echo.
+
+rem Flash the HEX-file.
+echo "Flash the HEX-file."
+%AVRDUDE% -c avrisp2 -p m328p -P usb -U flash:w:%HEX%:i
+echo.
+
+rem Verify the flash.
+echo "Verify the flash."
+%AVRDUDE% -c avrisp2 -p m328p -P usb -U flash:v:%HEX%:i
+echo.