diff --git a/rtl/sync/taxi_sync_reset.sv b/rtl/sync/taxi_sync_reset.sv
index 108f037..00fc8e9 100644
--- a/rtl/sync/taxi_sync_reset.sv
+++ b/rtl/sync/taxi_sync_reset.sv
@@ -28,7 +28,7 @@ module taxi_sync_reset #
     output wire logic  out
 );
 
-(* srl_style = "register" *)
+(* async_reg="true", srl_style="register", shreg_extract="no" *)
 logic [N-1:0] sync_reg = '1;
 
 assign out = sync_reg[N-1];
diff --git a/rtl/sync/taxi_sync_signal.sv b/rtl/sync/taxi_sync_signal.sv
index 96cc510..e0da3a2 100644
--- a/rtl/sync/taxi_sync_signal.sv
+++ b/rtl/sync/taxi_sync_signal.sv
@@ -29,7 +29,7 @@ module taxi_sync_signal #(
     output wire logic [WIDTH-1:0]  out
 );
 
-(* srl_style = "register" *)
+(* async_reg="true", srl_style="register", shreg_extract="no" *)
 logic [WIDTH-1:0] sync_reg[N-1:0];
 
 assign out = sync_reg[N-1];
diff --git a/syn/vivado/taxi_sync_reset.tcl b/syn/vivado/taxi_sync_reset.tcl
index 5c86fa2..a6958f4 100644
--- a/syn/vivado/taxi_sync_reset.tcl
+++ b/syn/vivado/taxi_sync_reset.tcl
@@ -14,6 +14,5 @@ foreach inst [get_cells -hier -filter {(ORIG_REF_NAME == taxi_sync_reset || REF_
     # reset synchronization
     set reset_ffs [get_cells -quiet -hier "sync_reg_reg[*]" -filter "PARENT == $inst"]
 
-    set_property ASYNC_REG TRUE $reset_ffs
     set_false_path -to [get_pins -of_objects $reset_ffs -filter {IS_PRESET || IS_RESET}]
 }
diff --git a/syn/vivado/taxi_sync_signal.tcl b/syn/vivado/taxi_sync_signal.tcl
index 176852a..cf5e8e9 100644
--- a/syn/vivado/taxi_sync_signal.tcl
+++ b/syn/vivado/taxi_sync_signal.tcl
@@ -11,6 +11,5 @@
 foreach inst [get_cells -hier -filter {(ORIG_REF_NAME == taxi_sync_signal || REF_NAME == taxi_sync_signal)}] {
     puts "Inserting timing constraints for taxi_sync_signal instance $inst"
 
-    set_property ASYNC_REG TRUE [get_cells -hier "sync_reg_reg[*][*]" -filter "PARENT == $inst"]
     set_false_path -to [get_cells -hier "sync_reg_reg[0][*]" -filter "PARENT == $inst"]
 }