diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0c13acd8..4aa8726b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -110,6 +110,14 @@ set_target_properties(${EXE_NAME} PROPERTIES ADDITIONAL_CLEAN_FILES ${EXE_NAME}.
 # Force linker to ignore RWX segment warning even if cache exists
 target_link_options(${EXE_NAME} PRIVATE -Wl,--no-warn-rwx-segment)
 
+# ENABLE_NO_HEAP: no malloc/sbrk is linked (libc is discarded in py32f071xb.ld),
+# so the reserved heap is dead weight. Zero it to reclaim ~512 B of RAM. This is
+# a global toolchain optimization, independent of multiboot. The linker script
+# reads __min_heap_size when defined, else keeps its 0x200 default.
+if(ENABLE_NO_HEAP)
+    target_link_options(${EXE_NAME} PRIVATE "-Wl,--defsym=__min_heap_size=0")
+endif()
+
 # -----------------------------------
 #  Post build processing
 #
diff --git a/Core/py32f071xb.ld b/Core/py32f071xb.ld
index 62732d35..b35cac18 100644
--- a/Core/py32f071xb.ld
+++ b/Core/py32f071xb.ld
@@ -55,7 +55,9 @@ ENTRY(Reset_Handler)
 /* Highest address of the user mode stack */
 _estack = ORIGIN(RAM) + LENGTH(RAM);    /* end of RAM */
 /* Generate a link error if heap and stack don't fit into RAM */
-_Min_Heap_Size = 0x200;      /* required amount of heap  */
+/* ENABLE_NO_HEAP passes --defsym=__min_heap_size=0 to drop the reserved heap
+ * (no malloc/sbrk is linked); default stays 0x200 otherwise. */
+_Min_Heap_Size = DEFINED(__min_heap_size) ? __min_heap_size : 0x200;      /* required amount of heap  */
 _Min_Stack_Size = 0x400; /* required amount of stack */
 
 /* Specify the memory areas */