diff --git a/arch/Kconfig b/arch/Kconfig
index 1c8903a021..f750b8f509 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -85,6 +85,7 @@ config ARCH_SIM
 	select ARCH_HAVE_TESTSET
 	select ARCH_HAVE_VFORK
 	select ARCH_HAVE_SETJMP
+	select ARCH_HAVE_CUSTOMOPT
 	select ARCH_SETJMP_H
 	select ALARM_ARCH
 	select ONESHOT
diff --git a/boards/sim/sim/sim/scripts/Make.defs b/boards/sim/sim/sim/scripts/Make.defs
index dc9ca66987..8dedaace16 100644
--- a/boards/sim/sim/sim/scripts/Make.defs
+++ b/boards/sim/sim/sim/scripts/Make.defs
@@ -45,8 +45,14 @@ ifeq ($(CONFIG_DEBUG_SYMBOLS),y)
   ARCHOPTIMIZATIONRUST = -g
 endif
 
+ifeq ($(CONFIG_DEBUG_CUSTOMOPT),y)
+  MAXOPTIMIZATION := $(CONFIG_DEBUG_OPTLEVEL)
+else
+  MAXOPTIMIZATION ?= -O2
+endif
+
 ifneq ($(CONFIG_DEBUG_NOOPT),y)
-  ARCHOPTIMIZATION += -O2 -fno-strict-aliasing
+  ARCHOPTIMIZATION += $(MAXOPTIMIZATION) -fno-strict-aliasing
 else
   ARCHOPTIMIZATIONRUST += -C opt-level=0
 endif