diff --git a/openfpga_flow/openfpga_arch/k4_N4_40nm_subtile_annotation_openfpga.xml b/openfpga_flow/openfpga_arch/k4_N4_40nm_subtile_annotation_openfpga.xml
index 429b48947..bbe32024a 100644
--- a/openfpga_flow/openfpga_arch/k4_N4_40nm_subtile_annotation_openfpga.xml
+++ b/openfpga_flow/openfpga_arch/k4_N4_40nm_subtile_annotation_openfpga.xml
@@ -149,15 +149,20 @@
       <port type="output" prefix="QN" size="1"/>
       <port type="clock" prefix="prog_clk" lib_name="CK" size="1" is_global="true" default_val="0" is_prog="true"/>
     </circuit_model>
-    <circuit_model type="iopad" name="GPIO" prefix="GPIO" spice_netlist="${OPENFPGA_PATH}/openfpga_flow/openfpga_cell_library/spice/gpio.sp" verilog_netlist="${OPENFPGA_PATH}/openfpga_flow/openfpga_cell_library/verilog/gpio.v">
+    <circuit_model type="iopad" name="GPIN" prefix="GPIN" is_default="true" verilog_netlist="${OPENFPGA_PATH}/openfpga_flow/openfpga_cell_library/verilog/gpio.v">
       <design_technology type="cmos"/>
-      <input_buffer exist="true" circuit_model_name="INVTX1"/>
-      <output_buffer exist="true" circuit_model_name="INVTX1"/>
-      <port type="inout" prefix="PAD" size="1" is_global="true" is_io="true" is_data_io="true"/>
-      <port type="sram" prefix="DIR" size="1" mode_select="true" circuit_model_name="DFF" default_val="1"/>
-      <port type="input" prefix="outpad" lib_name="A" size="1"/>
+      <input_buffer exist="true" circuit_model_name="sky130_fd_sc_hd__inv_1"/>
+      <output_buffer exist="true" circuit_model_name="sky130_fd_sc_hd__inv_1"/>
+      <port type="inout" prefix="PAD" lib_name="A" size="1" is_global="true" is_io="true" is_data_io="true"/>
       <port type="output" prefix="inpad" lib_name="Y" size="1"/>
     </circuit_model>
+    <circuit_model type="iopad" name="GPOUT" prefix="GPOUT" is_default="false" verilog_netlist="${OPENFPGA_PATH}/openfpga_flow/openfpga_cell_library/verilog/gpio.v">
+      <design_technology type="cmos"/>
+      <input_buffer exist="true" circuit_model_name="sky130_fd_sc_hd__inv_1"/>
+      <output_buffer exist="true" circuit_model_name="sky130_fd_sc_hd__inv_1"/>
+      <port type="inout" prefix="PAD" lib_name="Y" size="1" is_global="true" is_io="true" is_data_io="true"/>
+      <port type="input" prefix="outpad" lib_name="A" size="1"/>
+    </circuit_model>
   </circuit_library>
   <configuration_protocol>
     <organization type="scan_chain" circuit_model_name="DFF"/>
@@ -181,15 +186,12 @@
     <pb_type name="fpga_input" physical_mode_name="physical"/>
     <pb_type name="fpga_output" physical_mode_name="physical"/>
 
-    <pb_type name="fpga_input[physical].iopad" circuit_model_name="GPIO" mode_bits="0">
-      <port name="inpad" physical_mode_port="inpad"/>
-    </pb_type>
-    <pb_type name="fpga_output[physical].iopad" circuit_model_name="GPIO" mode_bits="0">
-      <port name="outpad" physical_mode_port="outpad"/>
-    </pb_type>
+    <pb_type name="fpga_input[physical].iopad" circuit_model_name="GPIN"/>
+    <pb_type name="fpga_output[physical].iopad" circuit_model_name="GPOUT"/>
+
+    <pb_type name="fpga_input[inpad].inpad" physical_pb_type_name="fpga_input[physical].iopad"/>
+    <pb_type name="fpga_output[outpad].outpad" physical_pb_type_name="fpga_output[physical].iopad"/>
 
-    <pb_type name="fpga_input[inpad].inpad" physical_pb_type_name="fpga_input[physical].iopad" mode_bits="1"/>
-    <pb_type name="fpga_output[outpad].outpad" physical_pb_type_name="fpga_output[physical].iopad" mode_bits="0"/>
     <!-- End physical pb_type binding in complex block IO -->
     <!-- physical pb_type binding in complex block CLB -->
     <!-- physical mode will be the default mode if not specified -->