4 files changed, 4 insertions, 3 deletions
diff --git a/demos/various/RT-Win32-Simulator/Makefile b/demos/various/RT-Win32-Simulator/Makefile
index cc5c62746..198df909e 100644
--- a/demos/various/RT-Win32-Simulator/Makefile
+++ b/demos/various/RT-Win32-Simulator/Makefile
@@ -5,7 +5,7 @@
 
 # Compiler options here.
 ifeq ($(USE_OPT),)
-  USE_OPT = -O2 -ggdb
+  USE_OPT = -O0 -ggdb
 endif
 
 # C specific options here (added to USE_OPT).
diff --git a/demos/various/RT-Win32-Simulator/chconf.h b/demos/various/RT-Win32-Simulator/chconf.h
index 63668c135..0b0831730 100644
--- a/demos/various/RT-Win32-Simulator/chconf.h
+++ b/demos/various/RT-Win32-Simulator/chconf.h
@@ -419,7 +419,7 @@
  *
  * @note    The default is @p FALSE.
  */
-#define CH_DBG_ENABLE_ASSERTS               FALSE
+#define CH_DBG_ENABLE_ASSERTS               TRUE
 
 /**
  * @brief   Debug option, trace buffer.
diff --git a/os/common/oslib/include/chheap.h b/os/common/oslib/include/chheap.h
index dad053368..be92ea423 100644
--- a/os/common/oslib/include/chheap.h
+++ b/os/common/oslib/include/chheap.h
@@ -84,7 +84,6 @@ typedef union heap_header heap_header_t;
  * @brief   Memory heap block header.
  */
 union heap_header {
-  stkalign_t align;
   struct {
     heap_header_t       *next;      /**< @brief Next block in free list.    */
     size_t              pages;      /**< @brief Size of the area in pages.  */
diff --git a/readme.txt b/readme.txt
index 7ec292323..f2da15a50 100644
--- a/readme.txt
+++ b/readme.txt
@@ -167,6 +167,8 @@
        dependencies and configuration directories. This makes possible
        to have multiple non-conflicting makefiles in the same project.
        Updated the various platform.mk implementing "smart build" mode.
+- LIB: Fixed heap allocator failing on simulators (bug #917)(backported
+       to 17.6.4).
 - STP: Fixed CRT0_FORCE_MSP_INIT flag not defaulted in crt0_v7m.S (bug #916)
        (backported to 17.6.4).
 - EX:  Improved MEMS drivers (bug #916)(backported to 17.6.4).