diff --git a/include/verilated.cpp b/include/verilated.cpp
index cb910e8a0..a56dcf5e0 100644
--- a/include/verilated.cpp
+++ b/include/verilated.cpp
@@ -1343,8 +1343,6 @@ void VL_FCLOSE_I(IData fdi) VL_MT_SAFE {
     VerilatedImp::fdClose(fdi);
 }
 
-void VL_FFLUSH_ALL() VL_MT_SAFE { fflush(stdout); }
-
 void VL_SFORMAT_X(int obits, CData& destr, const char* formatp, ...) VL_MT_SAFE {
     static VL_THREAD_LOCAL std::string t_output;  // static only for speed
     t_output = "";
diff --git a/nodist/code_coverage b/nodist/code_coverage
index 782bab1a7..eebc34d03 100755
--- a/nodist/code_coverage
+++ b/nodist/code_coverage
@@ -92,8 +92,8 @@ def test():
                 if re.search(regexp, dat):
                     # Remove .gcda/.gcno for files we don't care about before we slowly
                     # read them
-                    os.unlink(dat)
-                    os.unlink(gcno)
+                    unlink_ok(dat)
+                    unlink_ok(gcno)
                     del dats[dat]
                     break
 
@@ -315,6 +315,13 @@ def run(command):
         raise Exception("%Error: Command failed " + command + ", stopped")
 
 
+def unlink_ok(filename):
+    try:
+        os.unlink(filename)
+    except OSError:
+        pass
+
+
 def ci_fold_start(action):
     print("::group::" + action, flush=True)
 
diff --git a/test_regress/t/t_dpi_open_c.cpp b/test_regress/t/t_dpi_open_c.cpp
index cff5d506a..d75c822a1 100644
--- a/test_regress/t/t_dpi_open_c.cpp
+++ b/test_regress/t/t_dpi_open_c.cpp
@@ -161,6 +161,22 @@ void _dpii_all(int c, int p, int u, const svOpenArrayHandle i, const svOpenArray
             CHECK_RESULT_HEX(svSize(i, d), 7);
         }
     }
+#ifdef VERILATOR
+    // Check out-of-bounds read doesn't access bad memory (when sanitizer used)
+    (void)svLeft(i, -1);
+    (void)svRight(i, -1);
+    (void)svLow(i, -1);
+    (void)svHigh(i, -1);
+    (void)svIncrement(i, -1);
+    (void)svSize(i, -1);
+    //
+    (void)svLeft(i, 99);
+    (void)svRight(i, 99);
+    (void)svLow(i, 99);
+    (void)svHigh(i, 99);
+    (void)svIncrement(i, 99);
+    (void)svSize(i, 99);
+#endif
 
     if (c == 2 && p == 1 && u == 3) {
         for (int a = svLow(i, 1); a <= svHigh(i, 1); ++a) {
diff --git a/test_regress/t/t_enum_public.cpp b/test_regress/t/t_enum_public.cpp
index 328140331..e46b8d57d 100644
--- a/test_regress/t/t_enum_public.cpp
+++ b/test_regress/t/t_enum_public.cpp
@@ -12,6 +12,8 @@
 #include "Vt_enum_public_p3.h"
 #include "Vt_enum_public_p62.h"
 
+double sc_time_stamp() { return 0; }
+
 int main(int argc, char* argv[]) {
     Vt_enum_public* topp = new Vt_enum_public;
 
diff --git a/test_regress/t/t_string.v b/test_regress/t/t_string.v
index 6b8e48e07..758d5744e 100644
--- a/test_regress/t/t_string.v
+++ b/test_regress/t/t_string.v
@@ -15,6 +15,10 @@ module t (/*AUTOARG*/
 
    integer 	cyc=0;
 
+   reg [1*8:1] 	vstr1;
+   reg [2*8:1] 	vstr2;
+   reg [6*8:1] 	vstr6;
+
    reg [4*8:1] 	vstr;
    const string s = "a";  // Check static assignment
    string 	s2;
@@ -29,6 +33,15 @@ module t (/*AUTOARG*/
    // a.itoa, a.hextoa, a.octoa, a.bintoa, a.realtoa
 
    initial begin
+      $sformat(vstr1, "%s", s);
+      `checks(vstr1, "a");
+
+      $sformat(vstr2, "=%s", s);
+      `checks(vstr2, "=a");
+
+      $sformat(vstr6, "--a=%s", s);
+      `checks(vstr6, "--a=a");
+
       $sformat(vstr, "s=%s", s);
       `checks(vstr, "s=a");
       `checks(string'(vstr), "s=a");
diff --git a/test_regress/t/t_sys_plusargs.pl b/test_regress/t/t_sys_plusargs.pl
index 05eeca761..362a0c53c 100755
--- a/test_regress/t/t_sys_plusargs.pl
+++ b/test_regress/t/t_sys_plusargs.pl
@@ -16,7 +16,7 @@ compile(
 
 execute(
     check_finished => 1,
-    all_run_flags => ['+PLUS +INT=1234 +STRSTR +REAL=1.2345'],
+    all_run_flags => ['+PLUS +INT=1234 +STRSTR +REAL=1.2345 +IP%P101'],
     );
 
 ok(1);
diff --git a/test_regress/t/t_sys_plusargs.v b/test_regress/t/t_sys_plusargs.v
index f387b5fa2..015ccfb2c 100644
--- a/test_regress/t/t_sys_plusargs.v
+++ b/test_regress/t/t_sys_plusargs.v
@@ -89,6 +89,11 @@ module t;
       $display("str='%s'",sv_str);
       if (sv_str != "T=1234") $stop;
 
+      sv_str = "none";
+      if ($value$plusargs("IP%%P%b", p_i)!==1) $stop;
+      $display("str='%s'",sv_str);
+      if (p_i != 'b101) $stop;
+
       sv_in = "INT=%d";
 `ifdef VERILATOR
       if ($c1(0)) sv_in = "NEVER"; // Prevent constant propagation