diff --git a/hdk/cl/developer_designs/cl_firesim/build/scripts/create_dcp_from_cl.tcl b/hdk/cl/developer_designs/cl_firesim/build/scripts/create_dcp_from_cl.tcl
index 1cea9628..fad503db 100644
--- a/hdk/cl/developer_designs/cl_firesim/build/scripts/create_dcp_from_cl.tcl
+++ b/hdk/cl/developer_designs/cl_firesim/build/scripts/create_dcp_from_cl.tcl
@@ -38,6 +38,15 @@ set clock_recipe_c      [lindex $argv 10]
 set uram_option         [lindex $argv 11]
 set notify_via_sns      [lindex $argv 12]
 set VDEFINES            [lindex $argv 13]
+set reference_checkpoint [lindex $argv 14]
+
+
+if {$VDEFINES == "__NONE__"} {
+    # it is easier to explicitly pass something rather than having to get
+    # empty string passed correctly through layers of string interpolation
+    set VDEFINES ""
+}
+
 ##################################################
 ## Flow control variables 
 ##################################################
@@ -285,6 +294,14 @@ if {$implement} {
    }
    report_utilization -hierarchical -file $CL_DIR/build/reports/${timestamp}.post_opt_utilization.rpt
 
+   ########################
+   # Load Reference Checkpoint (if provided)
+   ########################
+   if {$reference_checkpoint != "__NONE__"} {
+       read_checkpoint -incremental $reference_checkpoint
+       report_incremental_reuse  -hierarchical -file $CL_DIR/build/reports/${timestamp}.post_opt_incremental_reuse.rpt 
+   }
+
    ########################
    # CL Place
    ########################
@@ -328,6 +345,10 @@ if {$implement} {
    # Report final timing
    report_timing_summary -file $CL_DIR/build/reports/${timestamp}.SH_CL_final_timing_summary.rpt
 
+   if {$reference_checkpoint != "__NONE__"} {
+       report_incremental_reuse  -hierarchical -file $CL_DIR/build/reports/${timestamp}.SH_CL_incremental_reuse.rpt 
+   }
+
    # Report utilization
    report_utilization -hierarchical -file $CL_DIR/build/reports/${timestamp}.SH_CL_utilization.rpt
 
diff --git a/hdk/cl/developer_designs/cl_firesim/build/scripts/synth_cl_firesim.tcl b/hdk/cl/developer_designs/cl_firesim/build/scripts/synth_cl_firesim.tcl
index 037ec3dd..7db0ceea 100644
--- a/hdk/cl/developer_designs/cl_firesim/build/scripts/synth_cl_firesim.tcl
+++ b/hdk/cl/developer_designs/cl_firesim/build/scripts/synth_cl_firesim.tcl
@@ -117,7 +117,9 @@ puts "AWS FPGA: ([clock format [clock seconds] -format %T]) Start design synthes
 
 update_compile_order -fileset sources_1
 puts "\nRunning synth_design for $CL_MODULE $CL_DIR/build/scripts \[[clock format [clock seconds] -format {%a %b %d %H:%M:%S %Y}]\]"
-eval [concat synth_design -top $CL_MODULE -verilog_define XSDB_SLV_DIS $VDEFINES -part [DEVICE_TYPE] -mode out_of_context $synth_options -directive $synth_directive]
+set runcmd [concat synth_design -top $CL_MODULE -verilog_define XSDB_SLV_DIS $VDEFINES -part [DEVICE_TYPE] -mode out_of_context $synth_options -directive $synth_directive]
+puts "\n$runcmd"
+eval $runcmd
 
 set failval [catch {exec grep "FAIL" failfast.csv}]
 if { $failval==0 } {
diff --git a/hdk/common/shell_v04261818/build/scripts/aws_build_dcp_from_cl.sh b/hdk/common/shell_v04261818/build/scripts/aws_build_dcp_from_cl.sh
index 75104d5c..5a2e68cb 100755
--- a/hdk/common/shell_v04261818/build/scripts/aws_build_dcp_from_cl.sh
+++ b/hdk/common/shell_v04261818/build/scripts/aws_build_dcp_from_cl.sh
@@ -18,7 +18,7 @@
 # Usage help
 function usage
 {
-    echo "usage: aws_build_dcp_from_cl.sh [ [-script <vivado_script>] | [-strategy BASIC | DEFAULT | EXPLORE | TIMING | NORETIMING | CONGESTION] [-clock_recipe_a A0 | A1 | A2] [-clock_recipe_b B0 | B1 | B2 | B3 | B4 | B5] [-clock_recipe_c C0 | C1 | C2 | C3] [-uram_option 2 | 3 | 4] [-vdefine macro1,macro2,macro3,.....,macrox] -foreground] [-notify] | [-h] | [-H] | [-help] ]"
+    echo "usage: aws_build_dcp_from_cl.sh [ [-script <vivado_script>] | [-strategy BASIC | DEFAULT | EXPLORE | TIMING | NORETIMING | CONGESTION] [-clock_recipe_a A0 | A1 | A2] [-clock_recipe_b B0 | B1 | B2 | B3 | B4 | B5] [-clock_recipe_c C0 | C1 | C2 | C3] [-uram_option 2 | 3 | 4] [-vdefine macro1,macro2,macro3,.....,macrox] -foreground] [-notify] [-reference_checkpoint <dcp>] | [-h] | [-H] | [-help] ]"
     echo " "
     echo "By default the build is run in the background using nohup so that the"
     echo "process will not be terminated if the terminal window is closed."
@@ -45,6 +45,7 @@ ignore_memory_requirement=0
 expected_memory_usage=30000000
 uram_option=2
 vdefine=""
+reference_checkpoint="__NONE__"
 
 function info_msg {
   echo -e "INFO: $1"
@@ -100,6 +101,9 @@ while [ "$1" != "" ]; do
                                 ;;
         -ignore_memory_requirement) ignore_memory_requirement=1
                                 ;;
+	-reference_checkpoint)  shift
+	                        reference_checkpoint=$1
+				;;
         -h | -H | -help )       usage
                                 exit
                                 ;;
@@ -162,7 +166,11 @@ do
  opt_vdefine+=" -verilog_define "
  opt_vdefine+=${vdefine_array[index]}
 done
-echo "$opt_vdefine"
+
+if [[ "$opt_vdefine" == "" ]]; then
+    opt_vdefine="__NONE__"
+fi
+info_msg "opt_vdefine is : $opt_vdefine"
 if [ $expected_memory_usage -gt `get_instance_memory` ]; then
 
     output_message="YOUR INSTANCE has less memory than is necessary for certain builds. This means that your builds will take longer than expected. \nTo change to an instance type with more memory, please check our instance resize guide: http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-resize.html"
@@ -243,7 +251,7 @@ subsystem_id="0x${id1_version:0:4}";
 subsystem_vendor_id="0x${id1_version:4:4}";
 
 # Run vivado
-cmd="vivado -mode batch -nojournal -log $logname -source $vivado_script -tclargs $timestamp $strategy $hdk_version $shell_version $device_id $vendor_id $subsystem_id $subsystem_vendor_id $clock_recipe_a $clock_recipe_b $clock_recipe_c $uram_option $notify $opt_vdefine"
+cmd="vivado -mode batch -nojournal -log $logname -source $vivado_script -tclargs $timestamp $strategy $hdk_version $shell_version $device_id $vendor_id $subsystem_id $subsystem_vendor_id $clock_recipe_a $clock_recipe_b $clock_recipe_c $uram_option $notify $opt_vdefine $reference_checkpoint"
 if [[ "$foreground" == "0" ]]; then
   nohup $cmd > $timestamp.nohup.out 2>&1 &