diff --git a/compiler.h b/compiler.h
index b847b6f05..eae1ec460 100644
--- a/compiler.h
+++ b/compiler.h
@@ -117,6 +117,9 @@ extern bool debug_emit;
 extern bool debug_synth2;
 extern bool debug_optimizer;
 
+/* Ignore errors about missing modules */
+extern bool ignore_missing_modules;
+
 /* Control evaluation of functions at compile time:
  *   0 = only for functions in constant expressions
  *   1 = only for automatic functions
diff --git a/driver/main.c b/driver/main.c
index a15235a98..0fe8130d1 100644
--- a/driver/main.c
+++ b/driver/main.c
@@ -38,7 +38,7 @@ const char NOTICE[] =
 ;
 
 const char HELP[] =
-"Usage: iverilog [-ESvV] [-B base] [-c cmdfile|-f cmdfile]\n"
+"Usage: iverilog [-EiSvV] [-B base] [-c cmdfile|-f cmdfile]\n"
 "                [-g1995|-g2001|-g2005|-g2005-sv|-g2009|-g2012] [-g<feature>]\n"
 "                [-D macro[=defn]] [-I includedir]\n"
 "                [-M [mode=]depfile] [-m module]\n"
@@ -140,6 +140,9 @@ int gen_relative_include = 0;
 
 char warning_flags[16] = "n";
 
+/* Boolean: true means ignore errors about missing modules */
+int ignore_missing_modules = 0;
+
 unsigned integer_width = 32;
 
 unsigned width_cap = 65536;
@@ -987,7 +990,7 @@ int main(int argc, char **argv)
 	}
       }
 
-      while ((opt = getopt(argc, argv, "B:c:D:d:Ef:g:hl:I:M:m:N:o:P:p:Ss:T:t:vVW:y:Y:")) != EOF) {
+      while ((opt = getopt(argc, argv, "B:c:D:d:Ef:g:hl:I:iM:m:N:o:P:p:Ss:T:t:vVW:y:Y:")) != EOF) {
 
 	    switch (opt) {
 		case 'B':
@@ -1042,6 +1045,10 @@ int main(int argc, char **argv)
 		  process_include_dir(optarg);
 		  break;
 
+		case 'i':
+  		  ignore_missing_modules = 1;
+  		  break;
+
 		case 'l':
 		  process_file_name(optarg, 1);
 		  break;
@@ -1184,6 +1191,7 @@ int main(int argc, char **argv)
       fprintf(iconfig_file, "generation:%s\n", gen_verilog_ams);
       fprintf(iconfig_file, "generation:%s\n", gen_icarus);
       fprintf(iconfig_file, "warnings:%s\n", warning_flags);
+      fprintf(iconfig_file, "ignore_missing_modules:%s\n", ignore_missing_modules ? "true" : "false");
       fprintf(iconfig_file, "out:%s\n", opath);
       if (depfile) {
             fprintf(iconfig_file, "depfile:%s\n", depfile);
diff --git a/elaborate.cc b/elaborate.cc
index a4245e67b..82b90fc7d 100644
--- a/elaborate.cc
+++ b/elaborate.cc
@@ -2204,8 +2204,10 @@ void PGModule::elaborate(Design*des, NetScope*scope) const
 	    return;
       }
 
-      cerr << get_fileline() << ": internal error: Unknown module type: " <<
-	    type_ << endl;
+      if (!ignore_missing_modules) {
+        cerr << get_fileline() << ": internal error: Unknown module type: " <<
+	      type_ << endl;
+      }
 }
 
 void PGModule::elaborate_scope(Design*des, NetScope*sc) const
@@ -2249,9 +2251,11 @@ void PGModule::elaborate_scope(Design*des, NetScope*sc) const
 
 	// Not a module or primitive that I know about or can find by
 	// any means, so give up.
-      cerr << get_fileline() << ": error: Unknown module type: " << type_ << endl;
-      missing_modules[type_] += 1;
-      des->errors += 1;
+      if (!ignore_missing_modules) {
+        cerr << get_fileline() << ": error: Unknown module type: " << type_ << endl;
+        missing_modules[type_] += 1;
+        des->errors += 1;
+      }
 }
 
 
diff --git a/main.cc b/main.cc
index 366ca150b..e814b7466 100644
--- a/main.cc
+++ b/main.cc
@@ -164,6 +164,11 @@ bool warn_sens_entire_arr = false;
 bool warn_anachronisms = false;
 bool warn_floating_nets = false;
 
+/*
+ * Ignore errors about missing modules
+ */
+bool ignore_missing_modules = false;
+
 /*
  * Debug message class flags.
  */
@@ -570,6 +575,9 @@ static bool set_default_timescale(const char*ts_string)
  *
  *    warnings:<string>
  *        Warning flag letters.
+ *
+ *    ignore_missing_modules:<bool>
+ *        true to ignore errors about missing modules
  */
 bool had_timescale = false;
 static void read_iconfig_file(const char*ipath)
@@ -720,6 +728,10 @@ static void read_iconfig_file(const char*ipath)
 			break;
 		  }
 
+		} else if (strcmp(buf, "ignore_missing_modules") == 0) {
+		  if (strcmp(cp, "true") == 0)
+		    ignore_missing_modules = true;
+
 	    } else if (strcmp(buf, "-y") == 0) {
 		  build_library_index(cp, CASE_SENSITIVE);