diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 551c7cb92..7edb1fcba 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -36,15 +36,23 @@ jobs:
       
     - name: Install Toolchains
       run: |
+        # ARM & RISC-V GCC from xpack
         npm install --global xpm
         xpm install --global @xpack-dev-tools/arm-none-eabi-gcc@latest
         xpm install --global @xpack-dev-tools/riscv-none-embed-gcc@latest
-        wget http://software-dl.ti.com/msp430/msp430_public_sw/mcu/msp430/MSPGCC/8_3_0_0/exports/msp430-gcc-8.3.0.16_linux64.tar.bz2 -O /tmp/msp430-gcc.tar.bz2
-        tar -C $HOME -xaf /tmp/msp430-gcc.tar.bz2
         echo "::add-path::`echo $HOME/opt/xPacks/@xpack-dev-tools/arm-none-eabi-gcc/*/.content/bin`"
         echo "::add-path::`echo $HOME/opt/xPacks/@xpack-dev-tools/riscv-none-embed-gcc/*/.content/bin`"
+
+        # TI MSP430 GCC
+        wget http://software-dl.ti.com/msp430/msp430_public_sw/mcu/msp430/MSPGCC/8_3_0_0/exports/msp430-gcc-8.3.0.16_linux64.tar.bz2 -O /tmp/msp430-gcc.tar.bz2
+        tar -C $HOME -xaf /tmp/msp430-gcc.tar.bz2
         echo "::add-path::`echo $HOME/msp430-gcc-*_linux64/bin`"
-      
+
+        # ESP IDF
+        git clone https://github.com/espressif/esp-idf.git $HOME/esp-idf
+        cd $HOME/esp-idf
+        ./install.sh
+
     - name: Checkout TinyUSB
       uses: actions/checkout@v2
     
@@ -54,5 +62,7 @@ jobs:
         git submodule update --init --recursive
     
     - name: Build
-      run: python3 tools/build_all.py ${{ matrix.example }}
+      run: |
+        . $HOME/esp-idf/export.sh
+        python3 tools/build_all.py ${{ matrix.example }}
 
diff --git a/.github/workflows/esp32s2.yml b/.github/workflows/esp32s2.yml
deleted file mode 100644
index a3f30c8f8..000000000
--- a/.github/workflows/esp32s2.yml
+++ /dev/null
@@ -1,38 +0,0 @@
-name: Build ESP32-S2
-
-on: [pull_request, push, repository_dispatch]
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        example: ['cdc_msc_freertos']
-        
-    steps:
-    - name: Setup Python
-      uses: actions/setup-python@v1
-      
-    - name: Install ESP-IDF
-      run: |
-        git clone https://github.com/espressif/esp-idf.git $HOME/esp-idf
-        cd $HOME/esp-idf
-        ./install.sh 
-        #echo "::add-path::`echo $HOME/msp430-gcc-*_linux64/bin`"
-      
-    - name: Checkout TinyUSB
-      uses: actions/checkout@v2
-    
-#    - name: Checkout Submodules
-#      run: |
-#        git submodule sync --recursive
-#        git submodule update --init --recursive
-    
-    - name: Build
-      run: |
-        . $HOME/esp-idf/export.sh
-        cd examples/device/cdc_msc_freertos
-        idf.py build
-        #python3 tools/build_all.py ${{ matrix.example }}
-
diff --git a/examples/rules.mk b/examples/rules.mk
index 55c70af4b..92204cf72 100644
--- a/examples/rules.mk
+++ b/examples/rules.mk
@@ -1,6 +1,25 @@
-#
-# Common make definition for all examples
-#
+# ---------------------------------------
+# Common make rules for all examples
+# ---------------------------------------
+
+ifeq ($(CROSS_COMPILE),xtensa-esp32-elf-)
+# Espressif IDF use CMake build system, this add wrapper target to call idf.py
+
+.PHONY: all clean flash
+.DEFAULT_GOAL := all
+
+all:
+	idf.py -B$(BUILD) -DBOARD=$(BOARD) build
+
+clean:
+	idf.py clean
+
+flash:
+	@:$(call check_defined, SERIAL, example: SERIAL=/dev/ttyUSB0)
+	idf.py -p $(SERIAL) flash
+
+else
+# GNU Make build system
 
 # libc
 LIBS += -lgcc -lm -lnosys
@@ -28,8 +47,9 @@ SRC_C += \
 # TinyUSB stack include
 INC += $(TOP)/src
 
-#
 CFLAGS += $(addprefix -I,$(INC))
+
+# TODO Skip nanolib for MSP430
 ifeq ($(BOARD), msp_exp430f5529lp)
   LDFLAGS += $(CFLAGS) -fshort-enums -Wl,-T,$(TOP)/$(LD_FILE) -Wl,-Map=$@.map -Wl,-cref -Wl,-gc-sections
 else
@@ -135,3 +155,5 @@ flash-jlink: $(BUILD)/$(BOARD)-firmware.hex
 # flash STM32 MCU using stlink with STM32 Cube Programmer CLI
 flash-stlink: $(BUILD)/$(BOARD)-firmware.elf
 	STM32_Programmer_CLI --connect port=swd --write $< --go
+
+endif # Make target
diff --git a/tools/build_all.py b/tools/build_all.py
index c95f88b79..a5e29a4ae 100644
--- a/tools/build_all.py
+++ b/tools/build_all.py
@@ -27,8 +27,7 @@ if len(sys.argv) > 2:
     all_boards.append(sys.argv[2])
 else:
     for entry in os.scandir("hw/bsp"):
-        # Skip board without board.mk e.g esp32s2
-        if entry.is_dir() and os.path.exists(entry.path + "/board.mk"):
+        if entry.is_dir():
             all_boards.append(entry.name)
 all_boards.sort()
 
@@ -40,7 +39,8 @@ def build_example(example, board):
                           stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
 
 def build_size(example, board):
-    elf_file = 'examples/device/{}/_build/build-{}/{}-firmware.elf'.format(example, board, board)
+    #elf_file = 'examples/device/{}/_build/build-{}/{}-firmware.elf'.format(example, board, board)
+    elf_file = 'examples/device/{}/_build/build-{}/*.elf'.format(example, board)
     size_output = subprocess.run('size {}'.format(elf_file), shell=True, stdout=subprocess.PIPE).stdout.decode("utf-8")
     size_list = size_output.split('\n')[1].split('\t')
     flash_size = int(size_list[0])
@@ -50,10 +50,18 @@ def build_size(example, board):
 def skip_example(example, board):
     ex_dir = 'examples/device/' + example
     board_mk = 'hw/bsp/{}/board.mk'.format(board)
-    for skip_file in glob.iglob(ex_dir + '/.skip.MCU_*'):
-        mcu_cflag = '-DCFG_TUSB_MCU=OPT_' + os.path.basename(skip_file).split('.')[2]
-        with open(board_mk) as mk:
-            if mcu_cflag in mk.read():
+
+    with open(board_mk) as mk:
+        mk_contents = mk.read()
+
+        # Skip ESP32-S2 board if example is not FreeRTOS one
+        if 'freertos' not in example and 'CROSS_COMPILE = xtensa-esp32-elf-' in mk_contents:
+            return 1
+
+        # Skip if CFG_TUSB_MCU in board.mk to match skip file
+        for skip_file in glob.iglob(ex_dir + '/.skip.MCU_*'):
+            mcu_cflag = '-DCFG_TUSB_MCU=OPT_' + os.path.basename(skip_file).split('.')[2]
+            if mcu_cflag in mk_contents:
                 return 1
 
     return 0