diff --git a/FreeRTOS-Plus/Demo/FreeRTOS_Plus_TCP_Echo_Qemu_mps2/init/startup.c b/FreeRTOS-Plus/Demo/FreeRTOS_Plus_TCP_Echo_Qemu_mps2/init/startup.c
index 7ae42769d0..06ea98b509 100644
--- a/FreeRTOS-Plus/Demo/FreeRTOS_Plus_TCP_Echo_Qemu_mps2/init/startup.c
+++ b/FreeRTOS-Plus/Demo/FreeRTOS_Plus_TCP_Echo_Qemu_mps2/init/startup.c
@@ -41,7 +41,10 @@ void __attribute__((weak)) EthernetISR (void);
 
 extern uint32_t _estack, _sidata, _sdata, _edata, _sbss, _ebss;
 
-__attribute__((naked)) void Reset_Handler(void)
+/* Prevent optimization so gcc does not replace code with memcpy */
+__attribute__((optimize("O0")))
+__attribute__((naked))
+void Reset_Handler(void)
  {
     // set stack pointer
     __asm volatile ("ldr r0, =_estack");
diff --git a/FreeRTOS/Demo/CORTEX_M3_MPS2_QEMU_GCC/init/startup.c b/FreeRTOS/Demo/CORTEX_M3_MPS2_QEMU_GCC/init/startup.c
index 7ae42769d0..1b09e8d9a1 100644
--- a/FreeRTOS/Demo/CORTEX_M3_MPS2_QEMU_GCC/init/startup.c
+++ b/FreeRTOS/Demo/CORTEX_M3_MPS2_QEMU_GCC/init/startup.c
@@ -41,8 +41,11 @@ void __attribute__((weak)) EthernetISR (void);
 
 extern uint32_t _estack, _sidata, _sdata, _edata, _sbss, _ebss;
 
-__attribute__((naked)) void Reset_Handler(void)
- {
+/* Prevent optimization so gcc does not replace code with memcpy */
+__attribute__((optimize("O0")))
+__attribute__((naked))
+void Reset_Handler(void)
+{
     // set stack pointer
     __asm volatile ("ldr r0, =_estack");
     __asm volatile ("mov sp, r0");