diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,11 @@
 # Copyright (c) 2017 The Bitcoin developers
 
 cmake_minimum_required(VERSION 3.12)
+
+set(CMAKE_USER_MAKE_RULES_OVERRIDE
+	"${CMAKE_SOURCE_DIR}/cmake/modules/OverrideInitFlags.cmake"
+)
+
 project(bitcoin-abc
 	VERSION 0.20.9
 	DESCRIPTION "Bitcoin ABC is a full node implementation of the Bitcoin Cash protocol."
diff --git a/cmake/modules/OverrideInitFlags.cmake b/cmake/modules/OverrideInitFlags.cmake
new file mode 100644
--- /dev/null
+++ b/cmake/modules/OverrideInitFlags.cmake
@@ -0,0 +1,15 @@
+# This will set the initial value for the C/CXX flags.
+# It is included at the time a project language is enabled.
+
+# This mimics the autotools behavior by setting the CFLAGS to '-g -O2`, which
+# are not well suited for debugging.
+# FIXME: update CFLAGS with better debug oriented optimization flags
+set(CMAKE_C_FLAGS_DEBUG_INIT "-g -O2")
+set(CMAKE_C_FLAGS_MINSIZEREL_INIT "-Os")
+set(CMAKE_C_FLAGS_RELEASE_INIT "-O3")
+set(CMAKE_C_FLAGS_RELWITHDEBINFO_INIT "-g -O2")
+
+set(CMAKE_CXX_FLAGS_DEBUG_INIT "-O0")
+set(CMAKE_CXX_FLAGS_MINSIZEREL_INIT "-Os")
+set(CMAKE_CXX_FLAGS_RELEASE_INIT "-O3")
+set(CMAKE_CXX_FLAGS_RELWITHDEBINFO_INIT "-g -O2")
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -40,22 +40,7 @@
 	endif()
 endif()
 
-# Cmake uses the CMAKE_BUILD_TYPE variable to select the build configuration.
-# By default it supports more configurations that needed for Bitcoin ABC, and
-# all the releases types set NDEBUG which is unwanted as it disables the assert
-# completely.
-# Remove the -DNDEBUG flag from the CFLAGS/CXXFLAGS in all the configurations
 include(AddCompilerFlags)
-remove_compiler_flags(-DNDEBUG)
-
-# Overrides the flags for the Debug build type
-# This mimics the autotools behavior by setting the CFLAGS to '-g -O2`, which
-# are not well suited for debugging.
-# FIXME: update CFLAGS with better debug oriented optimization flags
-set(CMAKE_C_FLAGS_DEBUG "-g -O2")
-
-# Disable all optimizations
-set(CMAKE_CXX_FLAGS_DEBUG -O0)
 # Prefer -g3, defaults to -g if unavailable
 add_cxx_compiler_flag_with_fallback(CMAKE_CXX_FLAGS_DEBUG -g3 -g)