diff --git a/hw/rtl/VX_platform.vh b/hw/rtl/VX_platform.vh
index 24f95069b..93b1b998c 100644
--- a/hw/rtl/VX_platform.vh
+++ b/hw/rtl/VX_platform.vh
@@ -157,7 +157,7 @@
 
 `ifdef QUARTUS
 `define MAX_FANOUT      8
-`define MAX_LUTRAM      1024
+`define FORCE_BRAM(d,w) (d >= 16 || w >= 128 || (d * w) >= 256)
 `define USE_BLOCK_BRAM  (* ramstyle = "block" *)
 `define USE_FAST_BRAM   (* ramstyle = "MLAB, no_rw_check" *)
 `define NO_RW_RAM_CHECK (* altera_attribute = "-name add_pass_through_logic_to_inferred_rams off" *)
@@ -168,7 +168,7 @@
 `define STRING          string
 `elsif VIVADO
 `define MAX_FANOUT      8
-`define MAX_LUTRAM      1024
+`define FORCE_BRAM(d,w) (d >= 16 || w >= 128 || (d * w) >= 256)
 `define USE_BLOCK_BRAM  (* ram_style = "block" *)
 `define USE_FAST_BRAM   (* ram_style = "distributed" *)
 `define NO_RW_RAM_CHECK (* rw_addr_collision = "no" *)
@@ -179,7 +179,7 @@
 `define STRING
 `else
 `define MAX_FANOUT      8
-`define MAX_LUTRAM      1024
+`define FORCE_BRAM(d,w) (d >= 16 || w >= 128 || (d * w) >= 256)
 `define USE_BLOCK_BRAM
 `define USE_FAST_BRAM
 `define NO_RW_RAM_CHECK
diff --git a/hw/rtl/cache/VX_cache.sv b/hw/rtl/cache/VX_cache.sv
index d4a3001ad..4643c8d9f 100644
--- a/hw/rtl/cache/VX_cache.sv
+++ b/hw/rtl/cache/VX_cache.sv
@@ -106,10 +106,9 @@ module VX_cache import VX_gpu_pkg::*; #(
     localparam MEM_ARB_SEL_BITS = `CLOG2(`CDIV(NUM_BANKS, MEM_PORTS));
     localparam MEM_ARB_SEL_WIDTH = `UP(MEM_ARB_SEL_BITS);
 
-    localparam CORE_RSP_REG_DISABLE = (NUM_BANKS != 1) || (NUM_REQS != 1);
-    localparam MEM_REQ_REG_DISABLE  = (NUM_BANKS != 1);
-
-    localparam REQ_XBAR_BUF = (NUM_REQS > 4) ? 2 : 0;
+    localparam REQ_XBAR_BUF    = (NUM_REQS > 2) ? 2 : 0;
+    localparam CORE_RSP_BUF_ENABLE = (NUM_BANKS != 1) || (NUM_REQS != 1);
+    localparam MEM_REQ_BUF_ENABLE = (NUM_BANKS != 1);
 
 `ifdef PERF_ENABLE
     wire [NUM_BANKS-1:0] perf_read_miss_per_bank;
@@ -133,7 +132,7 @@ module VX_cache import VX_gpu_pkg::*; #(
         .NUM_BANKS (NUM_BANKS),
         .UUID_WIDTH(UUID_WIDTH),
         .TAG_WIDTH (TAG_WIDTH),
-        .BANK_SEL_LATENCY (`TO_OUT_BUF_REG(REQ_XBAR_BUF)) // bank xbar latency
+        .BANK_SEL_LATENCY (`TO_OUT_BUF_REG(REQ_XBAR_BUF)) // request xbar latency
     ) flush_unit (
         .clk             (clk),
         .reset           (reset),
@@ -387,8 +386,8 @@ module VX_cache import VX_gpu_pkg::*; #(
             .UUID_WIDTH   (UUID_WIDTH),
             .TAG_WIDTH    (TAG_WIDTH),
             .FLAGS_WIDTH  (FLAGS_WIDTH),
-            .CORE_OUT_REG (CORE_RSP_REG_DISABLE ? 0 : 1),
-            .MEM_OUT_REG  (MEM_REQ_REG_DISABLE ? 0 : 1)
+            .CORE_OUT_REG (CORE_RSP_BUF_ENABLE ? 0 : `TO_OUT_BUF_REG(CORE_OUT_BUF)),
+            .MEM_OUT_REG  (MEM_REQ_BUF_ENABLE ? 0 : `TO_OUT_BUF_REG(MEM_OUT_BUF))
         ) bank (
             .clk                (clk),
             .reset              (reset),
@@ -481,7 +480,7 @@ module VX_cache import VX_gpu_pkg::*; #(
     for (genvar i = 0; i < NUM_REQS; ++i) begin : g_core_rsp_buf
         VX_elastic_buffer #(
             .DATAW   (`CS_WORD_WIDTH + TAG_WIDTH),
-            .SIZE    (CORE_RSP_REG_DISABLE ? `TO_OUT_BUF_SIZE(CORE_OUT_BUF) : 0),
+            .SIZE    (CORE_RSP_BUF_ENABLE ? `TO_OUT_BUF_SIZE(CORE_OUT_BUF) : 0),
             .OUT_REG (`TO_OUT_BUF_REG(CORE_OUT_BUF))
         ) core_rsp_buf (
             .clk       (clk),
@@ -578,7 +577,7 @@ module VX_cache import VX_gpu_pkg::*; #(
 
         VX_elastic_buffer #(
             .DATAW   (1 + LINE_SIZE + `CS_MEM_ADDR_WIDTH + `CS_LINE_WIDTH + MEM_TAG_WIDTH + `UP(FLAGS_WIDTH)),
-            .SIZE    (MEM_REQ_REG_DISABLE ? `TO_OUT_BUF_SIZE(MEM_OUT_BUF) : 0),
+            .SIZE    (MEM_REQ_BUF_ENABLE ? `TO_OUT_BUF_SIZE(MEM_OUT_BUF) : 0),
             .OUT_REG (`TO_OUT_BUF_REG(MEM_OUT_BUF))
         ) mem_req_buf (
             .clk       (clk),
diff --git a/hw/rtl/cache/VX_cache_top.sv b/hw/rtl/cache/VX_cache_top.sv
index f992c3613..ae8cc3fc6 100644
--- a/hw/rtl/cache/VX_cache_top.sv
+++ b/hw/rtl/cache/VX_cache_top.sv
@@ -153,7 +153,7 @@ module VX_cache_top import VX_gpu_pkg::*; #(
         assign mem_rsp_ready[i] = mem_bus_if[i].rsp_ready;
     end
 
-    VX_cache #(
+    VX_cache_wrap #(
         .INSTANCE_ID    (INSTANCE_ID),
         .CACHE_SIZE     (CACHE_SIZE),
         .LINE_SIZE      (LINE_SIZE),
diff --git a/hw/syn/altera/dut/unittest/Makefile b/hw/syn/altera/dut/unittest/Makefile
index c4479f154..3539c23b6 100644
--- a/hw/syn/altera/dut/unittest/Makefile
+++ b/hw/syn/altera/dut/unittest/Makefile
@@ -8,4 +8,5 @@ FPU_INCLUDE = -I$(RTL_DIR)/fpu
 ifneq (,$(findstring FPU_FPNEW,$(CONFIGS)))
 	FPU_INCLUDE += -J$(THIRD_PARTY_DIR)/cvfpu/src/common_cells/include -J$(THIRD_PARTY_DIR)/cvfpu/src/common_cells/src -J$(THIRD_PARTY_DIR)/cvfpu/src/fpu_div_sqrt_mvp/hdl -J$(THIRD_PARTY_DIR)/cvfpu/src
 endif
-RTL_INCLUDE = -I$(RTL_DIR) -I$(RTL_DIR)/libs -I$(RTL_DIR)/interfaces -I$(RTL_DIR)/core -I$(RTL_DIR)/mem -I$(RTL_DIR)/cache -I$(IP_CACHE_DIR) $(FPU_INCLUDE)
\ No newline at end of file
+RTL_INCLUDE = -I$(RTL_DIR) -I$(RTL_DIR)/libs -I$(RTL_DIR)/interfaces -I$(RTL_DIR)/core -I$(RTL_DIR)/mem -I$(RTL_DIR)/cache -I$(IP_CACHE_DIR) $(FPU_INCLUDE)
+RTL_INCLUDE = -I..
\ No newline at end of file
diff --git a/hw/syn/altera/opae/Makefile b/hw/syn/altera/opae/Makefile
index 61935f2e4..ff713e329 100644
--- a/hw/syn/altera/opae/Makefile
+++ b/hw/syn/altera/opae/Makefile
@@ -5,7 +5,6 @@ DEVICE_FAMILY ?= arria10
 
 PREFIX ?= build$(XLEN)
 TARGET ?= fpga
-NUM_CORES ?= 1
 
 SRC_DIR := $(VORTEX_HOME)/hw/syn/altera/opae
 
@@ -44,6 +43,7 @@ ifeq ($(DEVICE_FAMILY), arria10)
     CONFIGS += -DALTERA_A10
 endif
 
+ifdef NUM_CORES
 # cluster configuration
 CONFIGS_1c  := -DNUM_CLUSTERS=1 -DNUM_CORES=1
 CONFIGS_2c  := -DNUM_CLUSTERS=1 -DNUM_CORES=2
@@ -53,6 +53,7 @@ CONFIGS_16c	:= -DNUM_CLUSTERS=1 -DNUM_CORES=16
 CONFIGS_32c := -DNUM_CLUSTERS=2 -DNUM_CORES=16
 CONFIGS_64c := -DNUM_CLUSTERS=4 -DNUM_CORES=16
 CONFIGS += $(CONFIGS_$(NUM_CORES)c)
+endif
 
 # include sources
 RTL_PKGS = $(AFU_DIR)/local_mem_cfg_pkg.sv $(AFU_DIR)/ccip/ccip_if_pkg.sv
diff --git a/hw/syn/xilinx/README b/hw/syn/xilinx/README
index a1ca231fe..7fdca65d7 100644
--- a/hw/syn/xilinx/README
+++ b/hw/syn/xilinx/README
@@ -47,14 +47,18 @@ TARGET=hw PLATFORM=xilinx_u50_gen3x16_xdma_5_202210_1 make chipscope
 # analyze build report
 vitis_analyzer build_xilinx_u50_gen3x16_xdma_5_202210_1_hw_4c/bin/vortex_afu.xclbin.link_summary
 
-# resuming build for routing
+# resuming builds
+TARGET=hw PLATFORM=xilinx_u55c_gen3x16_xdma_3_202210_1 VPP_FLAGS="--from_step vpl.synth" make > build.log 2>&1 &
+TARGET=hw PLATFORM=xilinx_u55c_gen3x16_xdma_3_202210_1 VPP_FLAGS="--from_step vpl.impl" make > build.log 2>&1 &
+TARGET=hw PLATFORM=xilinx_u55c_gen3x16_xdma_3_202210_1 VPP_FLAGS="--from_step vpl.impl.opt_design" make > build.log 2>&1 &
+TARGET=hw PLATFORM=xilinx_u55c_gen3x16_xdma_3_202210_1 VPP_FLAGS="--from_step vpl.impl.place_design" make > build.log 2>&1 &
+TARGET=hw PLATFORM=xilinx_u55c_gen3x16_xdma_3_202210_1 VPP_FLAGS="--from_step vpl.impl.phys_opt_design" make > build.log 2>&1 &
 TARGET=hw PLATFORM=xilinx_u55c_gen3x16_xdma_3_202210_1 VPP_FLAGS="--from_step vpl.impl.route_design" make > build.log 2>&1 &
 
 # running test
 FPGA_BIN_DIR=<bin_dir> TARGET=hw_emu ./ci/blackbox.sh --driver=xrt --app=demo
-FPGA_BIN_DIR=<bin_dir> TARGET=hw ./ci/blackbox.sh --driver=xrt --app=demo
-FPGA_BIN_DIR=<bin_dir> TARGET=hw_emu ./ci/blackbox.sh --driver=xrt --app=demo
-FPGA_BIN_DIR=<bin_dir> XRT_DEVICE_INDEX=1 TARGET=hw ./ci/blackbox.sh --driver=xrt --app=demo
+FPGA_BIN_DIR=<bin_dir> TARGET=hw ./ci/blackbox.sh --driver=xrt --app=sgemm --args="-n1024"
+FPGA_BIN_DIR=<bin_dir> XRT_DEVICE_INDEX=1 TARGET=hw ./ci/blackbox.sh --driver=xrt --app=sgemm --args="-n1024"
 
 # build report logs
 <build_dir>/bin/vortex_afu.xclbin.info
diff --git a/hw/syn/xilinx/dut/common.mk b/hw/syn/xilinx/dut/common.mk
index 81946c88f..a3c3b9bc3 100644
--- a/hw/syn/xilinx/dut/common.mk
+++ b/hw/syn/xilinx/dut/common.mk
@@ -37,10 +37,15 @@ else
 endif
 
 clean:
+ifndef RESUME
 	rm -rf project_1
 	rm -rf .Xil
 	rm -f *.rpt
-	rm -f vivado*.log
-	rm -f vivado*.jou
+	rm -f *.log
+	rm -f *.jou
+	rm -f *.dcp
+else
+	@echo "RESUME is defined, skipping clean."
+endif
 
 .PHONY: all gen-sources build clean
\ No newline at end of file
diff --git a/hw/syn/xilinx/dut/project.tcl b/hw/syn/xilinx/dut/project.tcl
index 9cb173c22..fb84b586a 100644
--- a/hw/syn/xilinx/dut/project.tcl
+++ b/hw/syn/xilinx/dut/project.tcl
@@ -11,9 +11,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# Start time
-set start_time [clock seconds]
-
 if { $::argc != 4 } {
   puts "ERROR: Program \"$::argv0\" requires 4 arguments!\n"
   puts "Usage: $::argv0 <top_module> <device_part> <vcs_file> <xdc_file>\n"
@@ -46,95 +43,135 @@ if {[info exists ::env(MAX_JOBS)]} {
   set num_jobs 0
 }
 
-# create fpu ip
-if {[info exists ::env(FPU_IP)]} {
-  set ip_dir $::env(FPU_IP)
-  set argv [list $ip_dir $device_part]
-  set argc 2
-  source ${script_dir}/xilinx_ip_gen.tcl
+proc run_setup {} {
+  global project_name
+  global top_module device_part vcs_file xdc_file
+  global script_dir source_dir
+  global num_jobs
+  global argv argc ;# Using global system variables: argv and argc
+
+  # create fpu ip
+  if {[info exists ::env(FPU_IP)]} {
+    set ip_dir $::env(FPU_IP)
+    set argv [list $ip_dir $device_part]
+    set argc 2
+    source ${script_dir}/xilinx_ip_gen.tcl
+  }
+
+  source "${script_dir}/parse_vcs_list.tcl"
+  set vlist [parse_vcs_list "${vcs_file}"]
+
+  set vsources_list  [lindex $vlist 0]
+  set vincludes_list [lindex $vlist 1]
+  set vdefines_list  [lindex $vlist 2]
+
+  #puts $vsources_list
+  #puts $vincludes_list
+  #puts $vdefines_list
+  # Create project
+  create_project $project_name $project_name -force -part $device_part
+
+  # Add constrains file
+  read_xdc $xdc_file
+
+  # Add the design sources
+  add_files -norecurse -verbose $vsources_list
+
+  # process defines
+  set_property verilog_define ${vdefines_list} [current_fileset]
+
+  # add fpu ip
+  if {[info exists ::env(FPU_IP)]} {
+    set ip_dir $::env(FPU_IP)
+    add_files -norecurse -verbose ${ip_dir}/xil_fma/xil_fma.xci
+    add_files -norecurse -verbose ${ip_dir}/xil_fdiv/xil_fdiv.xci
+    add_files -norecurse -verbose ${ip_dir}/xil_fsqrt/xil_fsqrt.xci
+  }
+
+  # Synthesis
+  set_property top $top_module [current_fileset]
+  set_property \
+      -name {STEPS.SYNTH_DESIGN.ARGS.MORE OPTIONS} \
+      -value {-mode out_of_context -flatten_hierarchy "rebuilt"} \
+      -objects [get_runs synth_1]
+
+  # register compilation hooks
+  #set_property STEPS.SYNTH_DESIGN.TCL.PRE  ${source_dir}/pre_synth_hook.tcl  [get_runs synth_1]
+  #set_property STEPS.SYNTH_DESIGN.TCL.POST ${source_dir}/post_synth_hook.tcl [get_runs synth_1]
+  set_property STEPS.OPT_DESIGN.TCL.PRE    ${script_dir}/xilinx_async_bram_patch.tcl  [get_runs impl_1]
+  #set_property STEPS.OPT_DESIGN.TCL.POST   ${source_dir}/post_opt_hook.tcl   [get_runs impl_1]
+  #set_property STEPS.ROUTE_DESIGN.TCL.PRE  ${source_dir}/pre_route_hook.tcl  [get_runs impl_1]
+  #set_property STEPS.ROUTE_DESIGN.TCL.POST ${source_dir}/post_route_hook.tcl [get_runs impl_1]
+
+  update_compile_order -fileset sources_1
 }
 
-source "${script_dir}/parse_vcs_list.tcl"
-set vlist [parse_vcs_list "${vcs_file}"]
-
-set vsources_list  [lindex $vlist 0]
-set vincludes_list [lindex $vlist 1]
-set vdefines_list  [lindex $vlist 2]
-
-#puts $vsources_list
-#puts $vincludes_list
-#puts $vdefines_list
-
-# Create project
-create_project $project_name $project_name -force -part $device_part
+proc run_synthesis {} {
+  global num_jobs
+
+  if {$num_jobs != 0} {
+    launch_runs synth_1 -verbose -jobs $num_jobs
+  } else {
+    launch_runs synth_1 -verbose
+  }
+  wait_on_run synth_1
+  open_run synth_1
+  report_utilization -file post_synth_util.rpt -hierarchical -hierarchical_percentages
+  write_checkpoint -force post_synth.dcp
+}
 
-# Add constrains file
-read_xdc $xdc_file
+proc run_implementation {} {
+  global num_jobs
+
+  if {$num_jobs != 0} {
+    launch_runs impl_1 -verbose -jobs $num_jobs
+  } else {
+    launch_runs impl_1 -verbose
+  }
+  wait_on_run impl_1
+  open_run impl_1
+  report_utilization -file post_impl_util.rpt -hierarchical -hierarchical_percentages
+  write_checkpoint -force post_impl.dcp
+}
 
-# Add the design sources
-add_files -norecurse -verbose $vsources_list
+proc run_report {} {
+  # Generate the synthesis report
+  report_place_status -file place.rpt
+  report_route_status -file route.rpt
+  report_timing_summary -file timing.rpt
 
-# process defines
-set_property verilog_define ${vdefines_list} [current_fileset]
+  # Generate timing report
+  report_timing -nworst 100 -delay_type max -sort_by group -file timing.rpt
 
-# add fpu ip
-if {[info exists ::env(FPU_IP)]} {
-  set ip_dir $::env(FPU_IP)
-  add_files -norecurse -verbose ${ip_dir}/xil_fma/xil_fma.xci
-  add_files -norecurse -verbose ${ip_dir}/xil_fdiv/xil_fdiv.xci
-  add_files -norecurse -verbose ${ip_dir}/xil_fsqrt/xil_fsqrt.xci
+  # Generate power and drc reports
+  report_power -file power.rpt
+  report_drc -file drc.rpt
 }
 
-update_compile_order -fileset sources_1
-
-# Synthesis
-set_property top $top_module [current_fileset]
+###############################################################################
 
-set_property \
-    -name {STEPS.SYNTH_DESIGN.ARGS.MORE OPTIONS} \
-    -value {-mode out_of_context -flatten_hierarchy "rebuilt"} \
-    -objects [get_runs synth_1]
-
-# register compilation hooks
-#set_property STEPS.SYNTH_DESIGN.TCL.PRE  ${source_dir}/pre_synth_hook.tcl  [get_runs synth_1]
-#set_property STEPS.SYNTH_DESIGN.TCL.POST ${source_dir}/post_synth_hook.tcl [get_runs synth_1]
-set_property STEPS.OPT_DESIGN.TCL.PRE    ${script_dir}/xilinx_async_bram_patch.tcl  [get_runs impl_1]
-#set_property STEPS.OPT_DESIGN.TCL.POST   ${source_dir}/post_opt_hook.tcl   [get_runs impl_1]
-#set_property STEPS.ROUTE_DESIGN.TCL.PRE  ${source_dir}/pre_route_hook.tcl  [get_runs impl_1]
-#set_property STEPS.ROUTE_DESIGN.TCL.POST ${source_dir}/post_route_hook.tcl [get_runs impl_1]
+# Start time
+set start_time [clock seconds]
 
-if {$num_jobs != 0} {
-  launch_runs synth_1 -verbose -jobs $num_jobs
-} else {
-  launch_runs synth_1 -verbose
-}
-wait_on_run synth_1
-open_run synth_1
-write_checkpoint -force post_synth.dcp
-report_utilization -file post_synth_util.rpt -hierarchical -hierarchical_percentages
-
-# Implementation
-if {$num_jobs != 0} {
-  launch_runs impl_1 -verbose -jobs $num_jobs
+set checkpoint_synth "post_synth.dcp"
+set checkpoint_impl "post_impl.dcp"
+
+if { [file exists $checkpoint_impl] } {
+  puts "Resuming from post-implementation checkpoint: $checkpoint_impl"
+  open_checkpoint $checkpoint_impl
+  run_report
+} elseif { [file exists $checkpoint_synth] } {
+  puts "Resuming from post-synthesis checkpoint: $checkpoint_synth"
+  open_checkpoint $checkpoint_synth
+  run_implementation
+  run_report
 } else {
-  launch_runs impl_1 -verbose
+  # Execute full pipeline
+  run_setup
+  run_synthesis
+  run_implementation
+  run_report
 }
-wait_on_run impl_1
-open_run impl_1
-write_checkpoint -force post_impl.dcp
-report_utilization -file post_impl_util.rpt -hierarchical -hierarchical_percentages
-
-# Generate the synthesis report
-report_place_status -file place.rpt
-report_route_status -file route.rpt
-report_timing_summary -file timing.rpt
-
-# Generate timing report
-report_timing -nworst 10 -delay_type max -sort_by group -file timing.rpt
-
-# Generate power and drc reports
-report_power -file power.rpt
-report_drc -file drc.rpt
 
 # End time and calculation
 set elapsed_time [expr {[clock seconds] - $start_time}]
diff --git a/hw/syn/xilinx/sandbox/project.tcl.in b/hw/syn/xilinx/sandbox/project.tcl.in
index bb1bf86f2..b12d51d5b 100644
--- a/hw/syn/xilinx/sandbox/project.tcl.in
+++ b/hw/syn/xilinx/sandbox/project.tcl.in
@@ -458,7 +458,7 @@ if { [file exists post_impl.dcp] } {
   run_implementation
   run_report
 } else {
-  # execute full pipeline
+  # Execute full pipeline
   run_setup
   run_synthesis
   run_implementation
diff --git a/hw/syn/xilinx/xrt/Makefile b/hw/syn/xilinx/xrt/Makefile
index 288031e2e..936596671 100644
--- a/hw/syn/xilinx/xrt/Makefile
+++ b/hw/syn/xilinx/xrt/Makefile
@@ -15,7 +15,6 @@ endif
 TARGET ?= hw
 PLATFORM ?=
 
-NUM_CORES ?= 1
 PREFIX ?= build$(XLEN)
 MAX_JOBS ?= 8
 
@@ -64,6 +63,7 @@ DBG_SCOPE_FLAGS += -DDBG_SCOPE_ISSUE
 DBG_SCOPE_FLAGS += -DDBG_SCOPE_FETCH
 DBG_SCOPE_FLAGS += -DDBG_SCOPE_LSU
 
+ifdef NUM_CORES
 # cluster configuration
 CONFIGS_1c  := -DNUM_CLUSTERS=1 -DNUM_CORES=1
 CONFIGS_2c  := -DNUM_CLUSTERS=1 -DNUM_CORES=2
@@ -73,6 +73,7 @@ CONFIGS_16c	:= -DNUM_CLUSTERS=1 -DNUM_CORES=16
 CONFIGS_32c := -DNUM_CLUSTERS=2 -DNUM_CORES=16
 CONFIGS_64c := -DNUM_CLUSTERS=4 -DNUM_CORES=16
 CONFIGS += $(CONFIGS_$(NUM_CORES)c)
+endif
 
 # include sources
 RTL_PKGS = $(RTL_DIR)/VX_gpu_pkg.sv $(RTL_DIR)/fpu/VX_fpu_pkg.sv
diff --git a/hw/syn/yosys/Makefile b/hw/syn/yosys/Makefile
index a09d9198d..3e4d930e4 100644
--- a/hw/syn/yosys/Makefile
+++ b/hw/syn/yosys/Makefile
@@ -5,7 +5,6 @@ SRC_DIR := $(VORTEX_HOME)/hw/syn/yosys
 
 TOP_LEVEL_ENTITY ?= Vortex
 PREFIX ?= build
-NUM_CORES ?= 1
 
 SCRIPT_DIR := $(VORTEX_HOME)/hw/scripts
 RTL_DIR := $(VORTEX_HOME)/hw/rtl
@@ -30,7 +29,7 @@ DBG_SCOPE_FLAGS += -DDBG_SCOPE_ISSUE
 DBG_SCOPE_FLAGS += -DDBG_SCOPE_FETCH
 DBG_SCOPE_FLAGS += -DDBG_SCOPE_LSU
 
-
+ifdef NUM_CORES
 # cluster configuration
 CONFIGS_1c  := -DNUM_CLUSTERS=1 -DNUM_CORES=1
 CONFIGS_2c  := -DNUM_CLUSTERS=1 -DNUM_CORES=2
@@ -40,6 +39,7 @@ CONFIGS_16c	:= -DNUM_CLUSTERS=1 -DNUM_CORES=16 -DL2_ENABLE
 CONFIGS_32c := -DNUM_CLUSTERS=2 -DNUM_CORES=16 -DL2_ENABLE
 CONFIGS_64c := -DNUM_CLUSTERS=4 -DNUM_CORES=16 -DL2_ENABLE
 CONFIGS += $(CONFIGS_$(NUM_CORES)c)
+endif
 
 # include paths
 FPU_INCLUDE = -I$(RTL_DIR)/fpu