diff --git a/demos/STM32/RT-STM32G071RB-NUCLEO64/Makefile b/demos/STM32/RT-STM32G071RB-NUCLEO64/Makefile
index 4473a9239..ee6928c53 100644
--- a/demos/STM32/RT-STM32G071RB-NUCLEO64/Makefile
+++ b/demos/STM32/RT-STM32G071RB-NUCLEO64/Makefile
@@ -136,7 +136,7 @@ ASMXSRC = $(ALLXASMSRC)
 INCDIR = $(CONFDIR) $(ALLINC) $(TESTINC)
 
 # Define C warning options here.
-CWARN = -Wall -Wextra -Wundef -Wstrict-prototypes
+CWARN = -Wall -Wextra -Wundef -Wstrict-prototypes -Wcast-align=strict
 
 # Define C++ warning options here.
 CPPWARN = -Wall -Wextra -Wundef
diff --git a/demos/STM32/RT-STM32L552ZE-NUCLEO144-TZ_GUEST/Makefile b/demos/STM32/RT-STM32L552ZE-NUCLEO144-TZ_GUEST/Makefile
index 965443fb8..eb56db88c 100644
--- a/demos/STM32/RT-STM32L552ZE-NUCLEO144-TZ_GUEST/Makefile
+++ b/demos/STM32/RT-STM32L552ZE-NUCLEO144-TZ_GUEST/Makefile
@@ -136,7 +136,7 @@ ASMXSRC = $(ALLXASMSRC)
 INCDIR = $(CONFDIR) $(ALLINC) $(TESTINC)
 
 # Define C warning options here.
-CWARN = -Wall -Wextra -Wundef -Wstrict-prototypes
+CWARN = -Wall -Wextra -Wundef -Wstrict-prototypes -Wcast-align=strict
 
 # Define C++ warning options here.
 CPPWARN = -Wall -Wextra -Wundef
diff --git a/demos/STM32/RT-STM32L552ZE-NUCLEO144-TZ_HOST/Makefile b/demos/STM32/RT-STM32L552ZE-NUCLEO144-TZ_HOST/Makefile
index 7d1c71823..24843ce2a 100644
--- a/demos/STM32/RT-STM32L552ZE-NUCLEO144-TZ_HOST/Makefile
+++ b/demos/STM32/RT-STM32L552ZE-NUCLEO144-TZ_HOST/Makefile
@@ -137,7 +137,7 @@ ASMXSRC = $(ALLXASMSRC)
 INCDIR = $(CONFDIR) $(ALLINC) $(TESTINC)
 
 # Define C warning options here.
-CWARN = -Wall -Wextra -Wundef -Wstrict-prototypes
+CWARN = -Wall -Wextra -Wundef -Wstrict-prototypes -Wcast-align=strict
 
 # Define C++ warning options here.
 CPPWARN = -Wall -Wextra -Wundef
diff --git a/demos/STM32/RT-STM32L552ZE-NUCLEO144/Makefile b/demos/STM32/RT-STM32L552ZE-NUCLEO144/Makefile
index fa38622e3..acde1d6ca 100644
--- a/demos/STM32/RT-STM32L552ZE-NUCLEO144/Makefile
+++ b/demos/STM32/RT-STM32L552ZE-NUCLEO144/Makefile
@@ -136,7 +136,7 @@ ASMXSRC = $(ALLXASMSRC)
 INCDIR = $(CONFDIR) $(ALLINC) $(TESTINC)
 
 # Define C warning options here.
-CWARN = -Wall -Wextra -Wundef -Wstrict-prototypes
+CWARN = -Wall -Wextra -Wundef -Wstrict-prototypes -Wcast-align=strict
 
 # Define C++ warning options here.
 CPPWARN = -Wall -Wextra -Wundef
diff --git a/os/common/ports/ARMv6-M/chcore.h b/os/common/ports/ARMv6-M/chcore.h
index 18fc79ea4..4541e92c9 100644
--- a/os/common/ports/ARMv6-M/chcore.h
+++ b/os/common/ports/ARMv6-M/chcore.h
@@ -329,8 +329,8 @@ struct port_context {
  *          by an @p port_intctx structure.
  */
 #define PORT_SETUP_CONTEXT(tp, wbase, wtop, pf, arg) do {                   \
-  (tp)->ctx.sp = (struct port_intctx *)((uint8_t *)(wtop) -                 \
-                                        sizeof (struct port_intctx));       \
+  (tp)->ctx.sp = (struct port_intctx *)(void *)                             \
+                   ((uint8_t *)(wtop) - sizeof (struct port_intctx));       \
   (tp)->ctx.sp->r4 = (uint32_t)(pf);                                        \
   (tp)->ctx.sp->r5 = (uint32_t)(arg);                                       \
   (tp)->ctx.sp->lr = (uint32_t)__port_thread_start;                         \
diff --git a/os/common/ports/ARMv8-M-ML-TZ/chcore.h b/os/common/ports/ARMv8-M-ML-TZ/chcore.h
index 723159a77..33d0a3bca 100644
--- a/os/common/ports/ARMv8-M-ML-TZ/chcore.h
+++ b/os/common/ports/ARMv8-M-ML-TZ/chcore.h
@@ -534,8 +534,8 @@ struct port_context {
  */
 #define PORT_SETUP_CONTEXT(tp, wbase, wtop, pf, arg) do {                   \
   PORT_SETUP_CONTEXT_BASEPRI_NS(tp);                                        \
-  (tp)->ctx.sp = (struct port_intctx *)((uint8_t *)(wtop) -                 \
-                                        sizeof (struct port_intctx));       \
+  (tp)->ctx.sp = (struct port_intctx *)(void *)                             \
+                   ((uint8_t *)(wtop) - sizeof (struct port_intctx));       \
   (tp)->ctx.basepri     = CORTEX_BASEPRI_KERNEL;                            \
   (tp)->ctx.r5          = (uint32_t)(arg);                                  \
   (tp)->ctx.r4          = (uint32_t)(pf);                                   \
diff --git a/os/common/ports/ARMv8-M-ML/chcore.h b/os/common/ports/ARMv8-M-ML/chcore.h
index 4adc61fc7..547faf38d 100644
--- a/os/common/ports/ARMv8-M-ML/chcore.h
+++ b/os/common/ports/ARMv8-M-ML/chcore.h
@@ -427,8 +427,8 @@ struct port_context {
  *          by an @p port_intctx structure.
  */
 #define PORT_SETUP_CONTEXT(tp, wbase, wtop, pf, arg) do {                   \
-  (tp)->ctx.sp = (struct port_intctx *)((uint8_t *)(wtop) -                 \
-                                        sizeof (struct port_intctx));       \
+  (tp)->ctx.sp = (struct port_intctx *)(void *)                             \
+                   ((uint8_t *)(wtop) - sizeof (struct port_intctx));       \
   (tp)->ctx.sp->r4 = (uint32_t)(pf);                                        \
   (tp)->ctx.sp->r5 = (uint32_t)(arg);                                       \
   (tp)->ctx.sp->lr = (uint32_t)__port_thread_start;                         \
diff --git a/os/rt/src/chdynamic.c b/os/rt/src/chdynamic.c
index 391403f31..075666b7b 100644
--- a/os/rt/src/chdynamic.c
+++ b/os/rt/src/chdynamic.c
@@ -94,8 +94,8 @@ thread_t *chThdCreateFromHeap(memory_heap_t *heapp, size_t size,
   thread_descriptor_t td = THD_DESCRIPTOR(name, wbase, wend, prio, pf, arg);
 
 #if CH_DBG_FILL_THREADS == TRUE
-  __thd_memfill((uint8_t *)wsp,
-                (uint8_t *)wsp + size,
+  __thd_memfill((uint8_t *)wbase,
+                (uint8_t *)wbase + size,
                 CH_DBG_STACK_FILL_VALUE);
 #endif
 
@@ -152,8 +152,8 @@ thread_t *chThdCreateFromMemoryPool(memory_pool_t *mp, const char *name,
   thread_descriptor_t td = THD_DESCRIPTOR(name, wbase, wend, prio, pf, arg);
 
 #if CH_DBG_FILL_THREADS == TRUE
-  __thd_memfill((uint8_t *)wsp,
-                (uint8_t *)wsp + mp->object_size,
+  __thd_memfill((uint8_t *)wbase,
+                (uint8_t *)wbase + mp->object_size,
                 CH_DBG_STACK_FILL_VALUE);
 #endif
 
diff --git a/test/rt/testbuild/Makefile b/test/rt/testbuild/Makefile
index ccc29d839..bca7bf27e 100755
--- a/test/rt/testbuild/Makefile
+++ b/test/rt/testbuild/Makefile
@@ -153,10 +153,10 @@ BIN  = $(CP) -O binary
 COV  = gcov
 
 # Define C warning options here
-CWARN = -Wall -Wextra -Wundef -Wstrict-prototypes
+CWARN = -Wall -Wextra -Wundef -Wstrict-prototypes -Wcast-align=strict
 
 # Define C++ warning options here
-CPPWARN = -Wall -Wextra -Wundef -Wcast-align=strict
+CPPWARN = -Wall -Wextra -Wundef
 
 #
 # Compiler settings
diff --git a/test/rt/testbuild/Makefile_win32 b/test/rt/testbuild/Makefile_win32
index dacf86670..b26064e3e 100755
--- a/test/rt/testbuild/Makefile_win32
+++ b/test/rt/testbuild/Makefile_win32
@@ -153,10 +153,10 @@ BIN  = $(CP) -O binary
 COV  = gcov
 
 # Define C warning options here
-CWARN = -Wall -Wextra -Wundef -Wstrict-prototypes
+CWARN = -Wall -Wextra -Wundef -Wstrict-prototypes -Wcast-align=strict
 
 # Define C++ warning options here
-CPPWARN = -Wall -Wextra -Wundef -Wcast-align=strict
+CPPWARN = -Wall -Wextra -Wundef
 
 #
 # Compiler settings