diff --git a/os/kernel/include/heap.h b/os/kernel/include/heap.h
index c044f47c7..0ebe1d7b5 100644
--- a/os/kernel/include/heap.h
+++ b/os/kernel/include/heap.h
@@ -46,12 +46,15 @@ typedef struct memory_heap MemoryHeap;
 /**
  * @brief   Memory heap block header.
  */
-struct heap_header {
-  union {
-    struct heap_header  *next;      /**< @brief Next block in free list.    */
-    MemoryHeap          *heap;      /**< @brief Block owner heap.           */
-  } h_u;                            /**< @brief Overlapped fields.          */
-  size_t                h_size;     /**< @brief Size of the memory block.   */
+union heap_header {
+  stkalign_t align;
+  struct {
+    union {
+      union heap_header *next;      /**< @brief Next block in free list.    */
+      MemoryHeap        *heap;      /**< @brief Block owner heap.           */
+    } u;                            /**< @brief Overlapped fields.          */
+    size_t              size;       /**< @brief Size of the memory block.   */
+  } h;
 };
 
 /**
@@ -60,7 +63,7 @@ struct heap_header {
 struct memory_heap {
   memgetfunc_t          h_provider; /**< @brief Memory blocks provider for
                                                 this heap.                  */
-  struct heap_header    h_free;     /**< @brief Free blocks list header.    */
+  union heap_header     h_free;     /**< @brief Free blocks list header.    */
 #if CH_USE_MUTEXES
   Mutex                 h_mtx;      /**< @brief Heap access mutex.          */
 #else
diff --git a/os/kernel/include/memcore.h b/os/kernel/include/memcore.h
index 9fc8d7a44..c0aa9c9a2 100644
--- a/os/kernel/include/memcore.h
+++ b/os/kernel/include/memcore.h
@@ -28,11 +28,6 @@
 #ifndef _MEMCORE_H_
 #define _MEMCORE_H_
 
-/**
- * @brief   Memory alignment type.
- */
-typedef void *align_t;
-
 /**
  * @brief   Memory get function.
  * @note    This type must be assignment compatible with the @p chMemAlloc()
@@ -43,7 +38,7 @@ typedef void *(*memgetfunc_t)(size_t size);
 /**
  * @brief   Alignment mask constant.
  */
-#define MEM_ALIGN_MASK      (sizeof(align_t) - 1)
+#define MEM_ALIGN_MASK      (sizeof(stkalign_t) - 1)
 
 /**
  * @brief   Alignment helper macro.
diff --git a/os/kernel/src/chheap.c b/os/kernel/src/chheap.c
index 45431d5f4..91b7d01bc 100644
--- a/os/kernel/src/chheap.c
+++ b/os/kernel/src/chheap.c
@@ -53,8 +53,8 @@ static MemoryHeap default_heap;
  */
 void heap_init(void) {
   default_heap.h_provider = chCoreAlloc;
-  default_heap.h_free.h_u.next = (struct heap_header  *)NULL;
-  default_heap.h_free.h_size = 0;
+  default_heap.h_free.h.u.next = (union heap_header *)NULL;
+  default_heap.h_free.h.size = 0;
 #if CH_USE_MUTEXES
   chMtxInit(&default_heap.h_mtx);
 #else
@@ -72,15 +72,15 @@ void heap_init(void) {
  * @param[in] size      heap size
  */
 void chHeapInit(MemoryHeap *heapp, void *buf, size_t size) {
-  struct heap_header *hp;
+  union heap_header *hp;
 
   chDbgCheck(MEM_IS_ALIGNED(buf) && MEM_IS_ALIGNED(size), "chHeapInit");
 
   heapp->h_provider = (memgetfunc_t)NULL;
-  heapp->h_free.h_u.next = hp = buf;
-  heapp->h_free.h_size = 0;
-  hp->h_u.next = NULL;
-  hp->h_size = size - sizeof(struct heap_header);
+  heapp->h_free.h.u.next = hp = buf;
+  heapp->h_free.h.size = 0;
+  hp->h.u.next = NULL;
+  hp->h.size = size - sizeof(union heap_header);
 #if CH_USE_MUTEXES
   chMtxInit(&heapp->h_mtx);
 #else
@@ -103,7 +103,7 @@ void chHeapInit(MemoryHeap *heapp, void *buf, size_t size) {
  * @retval NULL         if the block cannot be allocated.
  */
 void *chHeapAlloc(MemoryHeap *heapp, size_t size) {
-  struct heap_header *qp, *hp, *fp;
+  union heap_header *qp, *hp, *fp;
 
   if (heapp == NULL)
     heapp = &default_heap;
@@ -112,24 +112,24 @@ void *chHeapAlloc(MemoryHeap *heapp, size_t size) {
   qp = &heapp->h_free;
   H_LOCK(heapp);
 
-  while (qp->h_u.next != NULL) {
-    hp = qp->h_u.next;
-    if (hp->h_size >= size) {
-      if (hp->h_size < size + sizeof(struct heap_header)) {
+  while (qp->h.u.next != NULL) {
+    hp = qp->h.u.next;
+    if (hp->h.size >= size) {
+      if (hp->h.size < size + sizeof(union heap_header)) {
         /* Gets the whole block even if it is slightly bigger than the
            requested size because the fragment would be too small to be
            useful.*/
-        qp->h_u.next = hp->h_u.next;
+        qp->h.u.next = hp->h.u.next;
       }
       else {
         /* Block bigger enough, must split it.*/
-        fp = (void *)((uint8_t *)(hp) + sizeof(struct heap_header) + size);
-        fp->h_u.next = hp->h_u.next;
-        fp->h_size = hp->h_size - sizeof(struct heap_header) - size;
-        qp->h_u.next = fp;
-        hp->h_size = size;
+        fp = (void *)((uint8_t *)(hp) + sizeof(union heap_header) + size);
+        fp->h.u.next = hp->h.u.next;
+        fp->h.size = hp->h.size - sizeof(union heap_header) - size;
+        qp->h.u.next = fp;
+        hp->h.size = size;
       }
-      hp->h_u.heap = heapp;
+      hp->h.u.heap = heapp;
 
       H_UNLOCK(heapp);
       return (void *)(hp + 1);
@@ -142,10 +142,10 @@ void *chHeapAlloc(MemoryHeap *heapp, size_t size) {
   /* More memory is required, tries to get it from the associated provider
      else fails.*/
   if (heapp->h_provider) {
-    hp = heapp->h_provider(size + sizeof(struct heap_header));
+    hp = heapp->h_provider(size + sizeof(union heap_header));
     if (hp != NULL) {
-      hp->h_u.heap = heapp;
-      hp->h_size = size;
+      hp->h.u.heap = heapp;
+      hp->h.size = size;
       hp++;
       return (void *)hp;
     }
@@ -153,9 +153,9 @@ void *chHeapAlloc(MemoryHeap *heapp, size_t size) {
   return NULL;
 }
 
-#define LIMIT(p) (struct heap_header *)((uint8_t *)(p) + \
-                                        sizeof(struct heap_header) + \
-                                        (p)->h_size)
+#define LIMIT(p) (union heap_header *)((uint8_t *)(p) + \
+                                        sizeof(union heap_header) + \
+                                        (p)->h.size)
 
 /**
  * @brief   Frees a previously allocated memory block.
@@ -163,13 +163,13 @@ void *chHeapAlloc(MemoryHeap *heapp, size_t size) {
  * @param[in] p         pointer to the memory block to be freed
  */
 void chHeapFree(void *p) {
-  struct heap_header *qp, *hp;
+  union heap_header *qp, *hp;
   MemoryHeap *heapp;
 
   chDbgCheck(p != NULL, "chHeapFree");
 
-  hp = (struct heap_header *)p - 1;
-  heapp = hp->h_u.heap;
+  hp = (union heap_header *)p - 1;
+  heapp = hp->h.u.heap;
   qp = &heapp->h_free;
   H_LOCK(heapp);
 
@@ -179,24 +179,24 @@ void chHeapFree(void *p) {
                 "within free block");
 
     if (((qp == &heapp->h_free) || (hp > qp)) &&
-        ((qp->h_u.next == NULL) || (hp < qp->h_u.next))) {
+        ((qp->h.u.next == NULL) || (hp < qp->h.u.next))) {
       /* Insertion after qp.*/
-      hp->h_u.next = qp->h_u.next;
-      qp->h_u.next = hp;
+      hp->h.u.next = qp->h.u.next;
+      qp->h.u.next = hp;
       /* Verifies if the newly inserted block should be merged.*/
-      if (LIMIT(hp) == hp->h_u.next) {
+      if (LIMIT(hp) == hp->h.u.next) {
         /* Merge with the next block.*/
-        hp->h_size += hp->h_u.next->h_size + sizeof(struct heap_header);
-        hp->h_u.next = hp->h_u.next->h_u.next;
+        hp->h.size += hp->h.u.next->h.size + sizeof(union heap_header);
+        hp->h.u.next = hp->h.u.next->h.u.next;
       }
       if ((LIMIT(qp) == hp)) {
         /* Merge with the previous block.*/
-        qp->h_size += hp->h_size + sizeof(struct heap_header);
-        qp->h_u.next = hp->h_u.next;
+        qp->h.size += hp->h.size + sizeof(union heap_header);
+        qp->h.u.next = hp->h.u.next;
       }
       break;
     }
-    qp = qp->h_u.next;
+    qp = qp->h.u.next;
   }
 
   H_UNLOCK(heapp);
@@ -217,7 +217,7 @@ void chHeapFree(void *p) {
  * @return              The number of fragments in the heap.
  */
 size_t chHeapStatus(MemoryHeap *heapp, size_t *sizep) {
-  struct heap_header *qp;
+  union heap_header *qp;
   size_t n, sz;
 
   if (heapp == NULL)
@@ -226,8 +226,8 @@ size_t chHeapStatus(MemoryHeap *heapp, size_t *sizep) {
   H_LOCK(heapp);
 
   sz = 0;
-  for (n = 0, qp = &heapp->h_free; qp->h_u.next; n++, qp = qp->h_u.next)
-    sz += qp->h_u.next->h_size;
+  for (n = 0, qp = &heapp->h_free; qp->h.u.next; n++, qp = qp->h.u.next)
+    sz += qp->h.u.next->h.size;
   if (sizep)
     *sizep = sz;
 
diff --git a/os/kernel/src/chmemcore.c b/os/kernel/src/chmemcore.c
index 8269deb48..d5adbef48 100644
--- a/os/kernel/src/chmemcore.c
+++ b/os/kernel/src/chmemcore.c
@@ -43,17 +43,19 @@ void core_init(void) {
   nextmem = &__heap_base__;
   endmem = &__heap_end__;
 #else
-  static align_t buffer[MEM_ALIGN_SIZE(CH_MEMCORE_SIZE) / sizeof(align_t)];
+  static stkalign_t buffer[MEM_ALIGN_SIZE(CH_MEMCORE_SIZE) /
+                           sizeof(stkalign_t)];
   nextmem = (uint8_t *)&buffer[0];
-  endmem = (uint8_t *)&buffer[MEM_ALIGN_SIZE(CH_MEMCORE_SIZE) / sizeof(align_t)];
+  endmem = (uint8_t *)&buffer[MEM_ALIGN_SIZE(CH_MEMCORE_SIZE) /
+                              sizeof(stkalign_t)];
 #endif
 }
 
 /**
  * @brief   Allocates a memory block.
  * @details The size of the returned block is aligned to the alignment
- *          type @p align_t so it is not possible to allocate less than
- *          <code>sizeof(align_t)</code>.
+ *          type @p stkalign_t so it is not possible to allocate less
+ *          than <code>sizeof(stkalign_t)</code>.
  *
  *
  * @param[in] size      the size of the block to be allocated
diff --git a/os/ports/GCC/SIMIA32/chcore.h b/os/ports/GCC/SIMIA32/chcore.h
index a0e26bf29..114e9ef43 100644
--- a/os/ports/GCC/SIMIA32/chcore.h
+++ b/os/ports/GCC/SIMIA32/chcore.h
@@ -36,9 +36,11 @@
 #define CH_ARCHITECTURE_NAME "x86 Simulator"
 
 /**
- * 32 bit stack alignment.
+ * 16 bytes stack alignment.
  */
-typedef uint32_t stkalign_t;
+typedef struct {
+  uint8_t a[16];
+} stkalign_t __attribute__((aligned(16)));
 
 /**
  * Generic x86 register.
diff --git a/readme.txt b/readme.txt
index 0c705159d..e207ac1aa 100644
--- a/readme.txt
+++ b/readme.txt
@@ -52,6 +52,8 @@
 *****************************************************************************
 
 *** 1.5.2 ***
+- FIX: Impossible to enforce alignment greater of a pointer size for heap/core
+  objects (bug 2952961)(backported in 1.4.1).
 - FIX: Wrong prototype in template file chcore.c (bug 2951529)(backported
   in 1.4.1).
 - NEW: Added BOARD_NAME macro to the various board.h files.