diff --git a/firmware/Makefile b/firmware/Makefile
index 2ba4791de5..ca84bac724 100644
--- a/firmware/Makefile
+++ b/firmware/Makefile
@@ -129,6 +129,12 @@ ifeq ($(USE_LTO),)
   USE_OPT += -flto=auto
 endif
 
+ifeq ($(OS),Windows_NT)
+   USE_OPT += -DIS_WINDOWS_COMPILER=1
+else
+   USE_OPT += -DIS_WINDOWS_COMPILER=0
+endif
+
 # If enabled, this option allows to compile the application in THUMB mode.
 ifeq ($(USE_THUMB),)
   USE_THUMB = yes
diff --git a/firmware/controllers/algo/engine_configuration.h b/firmware/controllers/algo/engine_configuration.h
index dfe889d678..75a42e89c9 100644
--- a/firmware/controllers/algo/engine_configuration.h
+++ b/firmware/controllers/algo/engine_configuration.h
@@ -21,8 +21,9 @@
 
 #define MOCK_UNDEFINED -1
 
-// why is Windows compiler not happy around simulator?! feature or defect?!
-#if !defined(EFI_SIM_IS_WINDOWS) || !EFI_SIM_IS_WINDOWS
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90826 Weak symbol does not work reliably on windows
+// https://sourceware.org/bugzilla/show_bug.cgi?id=9687 Weak symbols not working on mingw32
+#if !defined(IS_WINDOWS_COMPILER) || !IS_WINDOWS_COMPILER
 #define PUBLIC_API_WEAK_SOMETHING_WEIRD __attribute__((weak))
 #else
 #define PUBLIC_API_WEAK_SOMETHING_WEIRD
diff --git a/simulator/Makefile b/simulator/Makefile
index 9fce8cb178..9b061f7bff 100644
--- a/simulator/Makefile
+++ b/simulator/Makefile
@@ -54,9 +54,9 @@ ifeq ($(USE_OPT),)
   USE_OPT += -D US_TO_NT_MULTIPLIER=$(US_TO_NT_MULTIPLIER)
 
   ifeq ($(OS),Windows_NT)
-    USE_OPT += -DEFI_SIM_IS_WINDOWS=1
+    USE_OPT += -DEFI_SIM_IS_WINDOWS=1 -DIS_WINDOWS_COMPILER=1
   else
-    USE_OPT += -m32 -DEFI_SIM_IS_WINDOWS=0
+    USE_OPT += -m32 -DEFI_SIM_IS_WINDOWS=0 -DIS_WINDOWS_COMPILER=0
   endif
 endif
 
diff --git a/unit_tests/global_mocks.cpp b/unit_tests/global_mocks.cpp
index 74e3c7f79c..201b1f19d2 100644
--- a/unit_tests/global_mocks.cpp
+++ b/unit_tests/global_mocks.cpp
@@ -15,9 +15,6 @@ efitimems_t getTimeNowMs() {
 void initLogging(LoggingWithStorage *logging, const char *name) {
 }
 
-void setBoardConfigOverrides() {
-}
-
 void onCliCaseError(const char *token) {
 }
 
diff --git a/unit_tests/unit_test_rules.mk b/unit_tests/unit_test_rules.mk
index ae54260ee9..04a407bab4 100644
--- a/unit_tests/unit_test_rules.mk
+++ b/unit_tests/unit_test_rules.mk
@@ -147,6 +147,13 @@ CPPWARN = -Wall -Wextra -Wno-unused-parameter -Wno-unused-function -Wno-unused-v
 
 USE_OPT += -Werror=switch
 
+ifeq ($(OS),Windows_NT)
+   USE_OPT += -DIS_WINDOWS_COMPILER=1
+else
+   USE_OPT += -DIS_WINDOWS_COMPILER=0
+endif
+
+
 #
 # Compiler settings
 ##############################################################################