diff --git a/.github/scripts/dv/run-dv-wrapper.sh b/.github/scripts/dv/run-dv-wrapper.sh
index f431eca..f51560a 100644
--- a/.github/scripts/dv/run-dv-wrapper.sh
+++ b/.github/scripts/dv/run-dv-wrapper.sh
@@ -23,6 +23,7 @@
 
 export TARGET_PATH=$(pwd)
 export CARAVEL_ROOT=$(pwd)/caravel
+export PDK_ROOT=$(pwd)/pdks
 
 if [ ! -d $TARGET_PATH ] 
 then
@@ -32,8 +33,8 @@
 
 cd ..
 
-export PDK_PATH=$(pwd)/pdks/sky130A
-if [ ! -d $PDK_PATH ] 
+export PDK_ROOT=$(pwd)/pdks
+if [ ! -d $PDK_ROOT ] 
 then
     echo "Directory /path/to/dir DOES NOT exists." 
     exit 9999 
diff --git a/.gitignore b/.gitignore
index ed3bfef..f4e486c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1 @@
-checks/
\ No newline at end of file
+precheck_results
\ No newline at end of file
diff --git a/Makefile b/Makefile
index 3e6c335..25a5e72 100644
--- a/Makefile
+++ b/Makefile
@@ -144,7 +144,7 @@
 run-precheck: check-precheck check-pdk check-caravel
 	$(eval TARGET_PATH := $(shell pwd))
 	cd $(PRECHECK_ROOT) && \
-	docker run -v $(PRECHECK_ROOT):/usr/local/bin -v $(TARGET_PATH):$(TARGET_PATH) -v $(PDK_ROOT):$(PDK_ROOT) -v $(CARAVEL_ROOT):$(CARAVEL_ROOT) \
+	docker run -e TARGET_PATH=$(TARGET_PATH) -e PDK_ROOT=$(PDK_ROOT) -e CARAVEL_ROOT=$(CARAVEL_ROOT) -v $(PRECHECK_ROOT):/usr/local/bin -v $(TARGET_PATH):$(TARGET_PATH) -v $(PDK_ROOT):$(PDK_ROOT) -v $(CARAVEL_ROOT):$(CARAVEL_ROOT) \
 	-u $(shell id -u $(USER)):$(shell id -g $(USER)) efabless/open_mpw_precheck:latest bash -c "python3 open_mpw_prechecker.py --pdk_root $(PDK_ROOT) --target_path $(TARGET_PATH) -rfc -c $(CARAVEL_ROOT) "
 
 # Install PDK using OL's Docker Image
diff --git a/caravel b/caravel
index 6c9510b..13f2590 160000
--- a/caravel
+++ b/caravel
@@ -1 +1 @@
-Subproject commit 6c9510b578d9ffb1420d7d2c3a1bc988948f5283
+Subproject commit 13f2590e4b3a74b910dac56a6b757f5a66fd5212
diff --git a/verilog/dv/io_ports/Makefile b/verilog/dv/io_ports/Makefile
index 0ef079e..e3560d7 100644
--- a/verilog/dv/io_ports/Makefile
+++ b/verilog/dv/io_ports/Makefile
@@ -14,6 +14,9 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
+## PDK 
+PDK_PATH = $(PDK_ROOT)/sky130A
+
 ## Caravel Pointers
 CARAVEL_ROOT ?= ../../../caravel
 CARAVEL_PATH ?= $(CARAVEL_ROOT)
@@ -30,7 +33,6 @@
 ## RISCV GCC 
 GCC_PATH?=/ef/apps/bin
 GCC_PREFIX?=riscv32-unknown-elf
-PDK_PATH?=/ef/tech/SW/sky130A
 
 ## Simulation mode: RTL/GL
 SIM?=RTL
@@ -59,7 +61,7 @@
 %.vcd: %.vvp
 	vvp $<
 
-%.elf: %.c $(CARAVEL_FIRMWARE_PATH)/sections.lds $(CARAVEL_FIRMWARE_PATH)/start.s
+%.elf: %.c $(CARAVEL_FIRMWARE_PATH)/sections.lds $(CARAVEL_FIRMWARE_PATH)/start.s check-env
 	${GCC_PATH}/${GCC_PREFIX}-gcc -I $(CARAVEL_PATH) -march=rv32imc -mabi=ilp32 -Wl,-Bstatic,-T,$(CARAVEL_FIRMWARE_PATH)/sections.lds,--strip-debug -ffreestanding -nostdlib -o $@ $(CARAVEL_FIRMWARE_PATH)/start.s $<
 
 %.hex: %.elf
@@ -70,6 +72,17 @@
 %.bin: %.elf
 	${GCC_PATH}/${GCC_PREFIX}-objcopy -O binary $< /dev/stdout | tail -c +1048577 > $@
 
+check-env:
+ifndef PDK_ROOT
+	$(error PDK_ROOT is undefined, please export it before running make)
+endif
+ifeq (,$(wildcard $(PDK_ROOT)/sky130A))
+	$(error $(PDK_ROOT)/sky130A not found, please install pdk before running make)
+endif
+ifeq (,$(wildcard $(GCC_PATH)/$(GCC_PREFIX)-gcc ))
+	$(error $(GCC_PATH)/$(GCC_PREFIX)-gcc is not found, please export GCC_PATH and GCC_PREFIX before running make)
+endif
+
 # ---- Clean ----
 
 clean:
diff --git a/verilog/dv/la_test1/Makefile b/verilog/dv/la_test1/Makefile
index b23075d..14d6ee6 100644
--- a/verilog/dv/la_test1/Makefile
+++ b/verilog/dv/la_test1/Makefile
@@ -14,6 +14,9 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
+## PDK 
+PDK_PATH = $(PDK_ROOT)/sky130A
+
 ## Caravel Pointers
 CARAVEL_ROOT ?= ../../../caravel
 CARAVEL_PATH ?= $(CARAVEL_ROOT)
@@ -59,7 +62,7 @@
 %.vcd: %.vvp
 	vvp $<
 
-%.elf: %.c $(CARAVEL_FIRMWARE_PATH)/sections.lds $(CARAVEL_FIRMWARE_PATH)/start.s
+%.elf: %.c $(CARAVEL_FIRMWARE_PATH)/sections.lds $(CARAVEL_FIRMWARE_PATH)/start.s check-env
 	${GCC_PATH}/${GCC_PREFIX}-gcc -I $(CARAVEL_PATH) -march=rv32imc -mabi=ilp32 -Wl,-Bstatic,-T,$(CARAVEL_FIRMWARE_PATH)/sections.lds,--strip-debug -ffreestanding -nostdlib -o $@ $(CARAVEL_FIRMWARE_PATH)/start.s $<
 
 %.hex: %.elf
@@ -70,6 +73,17 @@
 %.bin: %.elf
 	${GCC_PATH}/${GCC_PREFIX}-objcopy -O binary $< /dev/stdout | tail -c +1048577 > $@
 
+check-env:
+ifndef PDK_ROOT
+	$(error PDK_ROOT is undefined, please export it before running make)
+endif
+ifeq (,$(wildcard $(PDK_ROOT)/sky130A))
+	$(error $(PDK_ROOT)/sky130A not found, please install pdk before running make)
+endif
+ifeq (,$(wildcard $(GCC_PATH)/$(GCC_PREFIX)-gcc ))
+	$(error $(GCC_PATH)/$(GCC_PREFIX)-gcc is not found, please export GCC_PATH and GCC_PREFIX before running make)
+endif
+
 # ---- Clean ----
 
 clean:
diff --git a/verilog/dv/la_test2/Makefile b/verilog/dv/la_test2/Makefile
index 14e48fc..46f127b 100644
--- a/verilog/dv/la_test2/Makefile
+++ b/verilog/dv/la_test2/Makefile
@@ -14,6 +14,9 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
+## PDK 
+PDK_PATH = $(PDK_ROOT)/sky130A
+
 ## Caravel Pointers
 CARAVEL_ROOT ?= ../../../caravel
 CARAVEL_PATH ?= $(CARAVEL_ROOT)
@@ -30,7 +33,6 @@
 ## RISCV GCC 
 GCC_PATH?=/ef/apps/bin
 GCC_PREFIX?=riscv32-unknown-elf
-PDK_PATH?=/ef/tech/SW/sky130A
 
 ## Simulation mode: RTL/GL
 SIM?=RTL
@@ -59,7 +61,7 @@
 %.vcd: %.vvp
 	vvp $<
 
-%.elf: %.c $(CARAVEL_FIRMWARE_PATH)/sections.lds $(CARAVEL_FIRMWARE_PATH)/start.s
+%.elf: %.c $(CARAVEL_FIRMWARE_PATH)/sections.lds $(CARAVEL_FIRMWARE_PATH)/start.s check-env
 	${GCC_PATH}/${GCC_PREFIX}-gcc -I $(CARAVEL_PATH) -march=rv32imc -mabi=ilp32 -Wl,-Bstatic,-T,$(CARAVEL_FIRMWARE_PATH)/sections.lds,--strip-debug -ffreestanding -nostdlib -o $@ $(CARAVEL_FIRMWARE_PATH)/start.s $<
 
 %.hex: %.elf
@@ -70,6 +72,17 @@
 %.bin: %.elf
 	${GCC_PATH}/${GCC_PREFIX}-objcopy -O binary $< /dev/stdout | tail -c +1048577 > $@
 
+check-env:
+ifndef PDK_ROOT
+	$(error PDK_ROOT is undefined, please export it before running make)
+endif
+ifeq (,$(wildcard $(PDK_ROOT)/sky130A))
+	$(error $(PDK_ROOT)/sky130A not found, please install pdk before running make)
+endif
+ifeq (,$(wildcard $(GCC_PATH)/$(GCC_PREFIX)-gcc ))
+	$(error $(GCC_PATH)/$(GCC_PREFIX)-gcc is not found, please export GCC_PATH and GCC_PREFIX before running make)
+endif
+
 # ---- Clean ----
 
 clean:
diff --git a/verilog/dv/mprj_stimulus/Makefile b/verilog/dv/mprj_stimulus/Makefile
index 304d32c..72818e3 100644
--- a/verilog/dv/mprj_stimulus/Makefile
+++ b/verilog/dv/mprj_stimulus/Makefile
@@ -14,6 +14,9 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
+## PDK 
+PDK_PATH = $(PDK_ROOT)/sky130A
+
 ## Caravel Pointers
 CARAVEL_ROOT ?= ../../../caravel
 CARAVEL_PATH ?= $(CARAVEL_ROOT)
@@ -30,7 +33,6 @@
 ## RISCV GCC 
 GCC_PATH?=/ef/apps/bin
 GCC_PREFIX?=riscv32-unknown-elf
-PDK_PATH?=/ef/tech/SW/sky130A
 
 ## Simulation mode: RTL/GL
 SIM?=RTL
@@ -59,7 +61,7 @@
 %.vcd: %.vvp
 	vvp $<
 
-%.elf: %.c $(CARAVEL_FIRMWARE_PATH)/sections.lds $(CARAVEL_FIRMWARE_PATH)/start.s
+%.elf: %.c $(CARAVEL_FIRMWARE_PATH)/sections.lds $(CARAVEL_FIRMWARE_PATH)/start.s check-env
 	${GCC_PATH}/${GCC_PREFIX}-gcc -I $(CARAVEL_PATH) -march=rv32imc -mabi=ilp32 -Wl,-Bstatic,-T,$(CARAVEL_FIRMWARE_PATH)/sections.lds,--strip-debug -ffreestanding -nostdlib -o $@ $(CARAVEL_FIRMWARE_PATH)/start.s $<
 
 %.hex: %.elf
@@ -70,6 +72,17 @@
 %.bin: %.elf
 	${GCC_PATH}/${GCC_PREFIX}-objcopy -O binary $< /dev/stdout | tail -c +1048577 > $@
 
+check-env:
+ifndef PDK_ROOT
+	$(error PDK_ROOT is undefined, please export it before running make)
+endif
+ifeq (,$(wildcard $(PDK_ROOT)/sky130A))
+	$(error $(PDK_ROOT)/sky130A not found, please install pdk before running make)
+endif
+ifeq (,$(wildcard $(GCC_PATH)/$(GCC_PREFIX)-gcc ))
+	$(error $(GCC_PATH)/$(GCC_PREFIX)-gcc is not found, please export GCC_PATH and GCC_PREFIX before running make)
+endif
+
 # ---- Clean ----
 
 clean:
diff --git a/verilog/dv/wb_port/Makefile b/verilog/dv/wb_port/Makefile
index 132a1cc..27c9715 100644
--- a/verilog/dv/wb_port/Makefile
+++ b/verilog/dv/wb_port/Makefile
@@ -14,6 +14,9 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
+## PDK 
+PDK_PATH = $(PDK_ROOT)/sky130A
+
 ## Caravel Pointers
 CARAVEL_ROOT ?= ../../../caravel
 CARAVEL_PATH ?= $(CARAVEL_ROOT)
@@ -30,7 +33,6 @@
 ## RISCV GCC 
 GCC_PATH?=/ef/apps/bin
 GCC_PREFIX?=riscv32-unknown-elf
-PDK_PATH?=/ef/tech/SW/sky130A
 
 ## Simulation mode: RTL/GL
 SIM?=RTL
@@ -59,7 +61,7 @@
 %.vcd: %.vvp
 	vvp $<
 
-%.elf: %.c $(CARAVEL_FIRMWARE_PATH)/sections.lds $(CARAVEL_FIRMWARE_PATH)/start.s
+%.elf: %.c $(CARAVEL_FIRMWARE_PATH)/sections.lds $(CARAVEL_FIRMWARE_PATH)/start.s check-env
 	${GCC_PATH}/${GCC_PREFIX}-gcc -I $(CARAVEL_PATH) -march=rv32imc -mabi=ilp32 -Wl,-Bstatic,-T,$(CARAVEL_FIRMWARE_PATH)/sections.lds,--strip-debug -ffreestanding -nostdlib -o $@ $(CARAVEL_FIRMWARE_PATH)/start.s $<
 
 %.hex: %.elf
@@ -70,6 +72,17 @@
 %.bin: %.elf
 	${GCC_PATH}/${GCC_PREFIX}-objcopy -O binary $< /dev/stdout | tail -c +1048577 > $@
 
+check-env:
+ifndef PDK_ROOT
+	$(error PDK_ROOT is undefined, please export it before running make)
+endif
+ifeq (,$(wildcard $(PDK_ROOT)/sky130A))
+	$(error $(PDK_ROOT)/sky130A not found, please install pdk before running make)
+endif
+ifeq (,$(wildcard $(GCC_PATH)/$(GCC_PREFIX)-gcc ))
+	$(error $(GCC_PATH)/$(GCC_PREFIX)-gcc is not found, please export GCC_PATH and GCC_PREFIX before running make)
+endif
+
 # ---- Clean ----
 
 clean:
diff --git a/verilog/gl/user_proj_example.v b/verilog/gl/user_proj_example.v
index 1ff3547..19f49ae 100644
--- a/verilog/gl/user_proj_example.v
+++ b/verilog/gl/user_proj_example.v
@@ -1,3 +1,18 @@
+// SPDX-FileCopyrightText: 2020 Efabless Corporation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// SPDX-License-Identifier: Apache-2.0
+
 module user_proj_example (wb_clk_i,
     wb_rst_i,
     wbs_ack_o,
diff --git a/verilog/gl/user_project_wrapper.v b/verilog/gl/user_project_wrapper.v
index 913e3ce..7ebcaf8 100644
--- a/verilog/gl/user_project_wrapper.v
+++ b/verilog/gl/user_project_wrapper.v
@@ -1,3 +1,18 @@
+// SPDX-FileCopyrightText: 2020 Efabless Corporation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// SPDX-License-Identifier: Apache-2.0
+
 module user_project_wrapper (user_clock2,
     wb_clk_i,
     wb_rst_i,