diff --git a/bsp/lm4f232/rtconfig.py b/bsp/lm4f232/rtconfig.py
index b34cab7f8e6cbbf9d5fe7c8acbdd4044853d5088..cfe518891b5a2f6685fcb054dbf9b3b336e69c2b 100644
--- a/bsp/lm4f232/rtconfig.py
+++ b/bsp/lm4f232/rtconfig.py
@@ -44,7 +44,7 @@ if PLATFORM == 'gcc':
 
     DEVICE = ' -mcpu=cortex-m4 -mthumb -mfpu=fpv4-sp-d16 -mfloat-abi=softfp -ffunction-sections -fdata-sections'
     CFLAGS = DEVICE 
-    AFLAGS = ' -c' + DEVICE + ' -x assembler-with-cpp -Wa,-mimplicit-it=thumb,'
+    AFLAGS = ' -c' + DEVICE + ' -x assembler-with-cpp -Wa,-mimplicit-it=thumb '
     LFLAGS = DEVICE + ' -Wl,--gc-sections,-Map=rtthread-lm4f.map,-cref,-u,Reset_Handler -T lm4f_rom.ld'
 
     CPATH = ''
diff --git a/bsp/stm32f40x/rtconfig.py b/bsp/stm32f40x/rtconfig.py
index 97ffb66f4754be53e25c0f807ecfbff75f80a77b..8621d6a099b5a12ff14453b9b1ee3d1a4d248d1f 100644
--- a/bsp/stm32f40x/rtconfig.py
+++ b/bsp/stm32f40x/rtconfig.py
@@ -42,7 +42,7 @@ if PLATFORM == 'gcc':
 
     DEVICE = ' -mcpu=cortex-m4 -mthumb -mfpu=fpv4-sp-d16 -mfloat-abi=softfp -ffunction-sections -fdata-sections'
     CFLAGS = DEVICE 
-    AFLAGS = ' -c' + DEVICE + ' -x assembler-with-cpp -Wa,-mimplicit-it=thumb,'
+    AFLAGS = ' -c' + DEVICE + ' -x assembler-with-cpp -Wa,-mimplicit-it=thumb '
     LFLAGS = DEVICE + ' -Wl,--gc-sections,-Map=rtthread-stm32.map,-cref,-u,Reset_Handler -T stm32_rom.ld'
 
     CPATH = ''
diff --git a/bsp/xplorer4330/m4/rtconfig.py b/bsp/xplorer4330/m4/rtconfig.py
index a691578c90ea05667b51ea1a66b389e7388d044b..0b61eda451155894d6dc1b1588c0daff8169f701 100644
--- a/bsp/xplorer4330/m4/rtconfig.py
+++ b/bsp/xplorer4330/m4/rtconfig.py
@@ -48,7 +48,7 @@ if PLATFORM == 'gcc':
 
     DEVICE = ' -mcpu=cortex-m4 -mthumb -mfpu=fpv4-sp-d16 -mfloat-abi=softfp -ffunction-sections -fdata-sections'
     CFLAGS = DEVICE 
-    AFLAGS = ' -c' + DEVICE + ' -x assembler-with-cpp -Wa,-mimplicit-it=thumb,'
+    AFLAGS = ' -c' + DEVICE + ' -x assembler-with-cpp -Wa,-mimplicit-it=thumb '
     LFLAGS = DEVICE + ' -Wl,--gc-sections,-Map=rtthread-lpc4330.map,-cref,-u,Reset_Handler -T lpc4330_xplorer_spifi32mb.ld'
 
     CPATH = ''