diff --git a/Demo/PPC405_FPU_Xilinx_Virtex4_GCC/__xps/rtosdemo_compiler.opt b/Demo/PPC405_FPU_Xilinx_Virtex4_GCC/__xps/rtosdemo_compiler.opt
index 25bf6ab97..2979e4328 100644
--- a/Demo/PPC405_FPU_Xilinx_Virtex4_GCC/__xps/rtosdemo_compiler.opt
+++ b/Demo/PPC405_FPU_Xilinx_Virtex4_GCC/__xps/rtosdemo_compiler.opt
@@ -3,7 +3,7 @@ RTOSDEMO_SOURCES = RTOSDemo/../../Common/Minimal/BlockQ.c RTOSDemo/../../Common/
 RTOSDEMO_HEADERS = RTOSDemo/FreeRTOSConfig.h 
 RTOSDEMO_CC = powerpc-eabi-gcc
 RTOSDEMO_CC_SIZE = powerpc-eabi-size
-RTOSDEMO_CC_OPT = -O2
+RTOSDEMO_CC_OPT = -O0
 RTOSDEMO_CFLAGS = -I./RTOSDemo/flop -I../../Source/portable/GCC/PPC405_Xilinx -I./ppc405_0/include/  -IRTOSDemo/   -I. -I./RTOSDemo/ -I../Common/include/ -I../../Source/include/ -I./ppc405_0/include/ -I./ppc405_0/include -D GCC_PPC405 -mregnames -Wextra
 RTOSDEMO_CC_SEARCH = # -B
 RTOSDEMO_LIBPATH = -L./ppc405_0/lib/ # -L
diff --git a/Demo/PPC405_FPU_Xilinx_Virtex4_GCC/system_incl.make b/Demo/PPC405_FPU_Xilinx_Virtex4_GCC/system_incl.make
index e01c87fef..7f558699b 100644
--- a/Demo/PPC405_FPU_Xilinx_Virtex4_GCC/system_incl.make
+++ b/Demo/PPC405_FPU_Xilinx_Virtex4_GCC/system_incl.make
@@ -123,7 +123,7 @@ RTOSDEMO_HEADERS = RTOSDemo/FreeRTOSConfig.h
 
 RTOSDEMO_CC = powerpc-eabi-gcc
 RTOSDEMO_CC_SIZE = powerpc-eabi-size
-RTOSDEMO_CC_OPT = -O2
+RTOSDEMO_CC_OPT = -O0
 RTOSDEMO_CFLAGS = -I./RTOSDemo/flop -I../../Source/portable/GCC/PPC405_Xilinx -I./ppc405_0/include/  -IRTOSDemo/   -I. -I./RTOSDemo/ -I../Common/include/ -I../../Source/include/ -I./ppc405_0/include/ -I./ppc405_0/include -D GCC_PPC405 -mregnames
 RTOSDEMO_CC_SEARCH = # -B
 RTOSDEMO_LIBPATH = -L./ppc405_0/lib/ # -L