diff --git a/rtl/serv_mpram.v b/rtl/serv_mpram.v
index 4db5bdf..40e5192 100644
--- a/rtl/serv_mpram.v
+++ b/rtl/serv_mpram.v
@@ -164,6 +164,10 @@ module serv_mpram
    end
 
 `ifdef RISCV_FORMAL
+ `define SERV_CLEAR_RAM
+`endif
+
+`ifdef SERV_CLEAR_RAM
    integer i;
    initial
      for (i=0;i<256;i=i+1)
diff --git a/rtl/serv_regfile.v b/rtl/serv_regfile.v
index 0140bdd..13c68d3 100644
--- a/rtl/serv_regfile.v
+++ b/rtl/serv_regfile.v
@@ -74,6 +74,10 @@ module serv_regfile
    end
 
 `ifdef RISCV_FORMAL
+ `define SERV_CLEAR_RAM
+`endif
+
+`ifdef SERV_CLEAR_RAM
    integer i;
    initial
      for (i=0;i<512;i=i+1)
diff --git a/serv.core b/serv.core
index ae4b1d8..88d6d95 100644
--- a/serv.core
+++ b/serv.core
@@ -24,7 +24,7 @@ filesets:
 targets:
   default:
     filesets : [core]
-    parameters : [RISCV_FORMAL]
+    parameters : [RISCV_FORMAL, SERV_CLEAR_RAM]
 
   lint:
     default_tool : verilator
@@ -39,3 +39,7 @@ parameters:
     datatype  : bool
     paramtype : vlogdefine
 
+  SERV_CLEAR_RAM:
+    datatype  : bool
+    paramtype : vlogdefine
+