diff --git a/Changes b/Changes
index 768f64b2c..11bc827bb 100644
--- a/Changes
+++ b/Changes
@@ -25,6 +25,8 @@ indicates the contributor was also the author of the fix; Thanks!
 
 ****  Fix gate primitives with arrays and non-arrayed pins.
 
+****  Fix DETECTARRAY error on packed arrays, bug770. [Jie Xu]
+
 ****  Fix ENDLABEL warnings on escaped identifiers.
 
 
diff --git a/src/V3Changed.cpp b/src/V3Changed.cpp
index 14857c300..542b8ac1b 100644
--- a/src/V3Changed.cpp
+++ b/src/V3Changed.cpp
@@ -83,17 +83,19 @@ private:
     void genChangeDet(AstVarScope* vscp) {
 	AstVar* varp = vscp->varp();
 	vscp->v3warn(IMPERFECTSCH,"Imperfect scheduling of variable: "<<vscp);
-	AstUnpackArrayDType* arrayp = varp->dtypeSkipRefp()->castUnpackArrayDType();
+	AstUnpackArrayDType* uarrayp = varp->dtypeSkipRefp()->castUnpackArrayDType();
+	AstPackArrayDType* parrayp = varp->dtypeSkipRefp()->castPackArrayDType();
 	AstNodeClassDType *classp = varp->dtypeSkipRefp()->castNodeClassDType();
-	bool isArray = arrayp;
+	bool isUnpackArray = uarrayp;
+	bool isPackArray = parrayp;
 	bool isClass = classp && classp->packedUnsup();
-	int elements = isArray ? arrayp->elementsConst() : 1;
-	if (isArray && (elements > DETECTARRAY_MAX_INDEXES)) {
+	int elements = isUnpackArray ? uarrayp->elementsConst() : 1;
+	if (isUnpackArray && (elements > DETECTARRAY_MAX_INDEXES)) {
 	    vscp->v3warn(E_DETECTARRAY, "Unsupported: Can't detect more than "<<cvtToStr(DETECTARRAY_MAX_INDEXES)
 			 <<" array indexes (probably with UNOPTFLAT warning suppressed): "<<varp->prettyName()<<endl
 			 <<vscp->warnMore()
 			 <<"... Could recompile with DETECTARRAY_MAX_INDEXES increased to at least "<<cvtToStr(elements));
-	} else if (!isArray && !isClass
+	} else if (!isUnpackArray && !isClass && !isPackArray
 		   && !varp->dtypeSkipRefp()->castBasicDType()) {
 	    if (debug()) varp->dumpTree(cout,"-DETECTARRAY-");
 	    vscp->v3warn(E_DETECTARRAY, "Unsupported: Can't detect changes on complex variable (probably with UNOPTFLAT warning suppressed): "<<varp->prettyName());
@@ -110,17 +112,17 @@ private:
 	    for (int index=0; index<elements; ++index) {
 		AstChangeDet* changep
 		    = new AstChangeDet (vscp->fileline(),
-					aselIfNeeded(isArray, index,
+					aselIfNeeded(isUnpackArray, index,
 						     new AstVarRef(vscp->fileline(), vscp, false)),
-					aselIfNeeded(isArray, index,
+					aselIfNeeded(isUnpackArray, index,
 						     new AstVarRef(vscp->fileline(), newvscp, false)),
 					false);
 		m_chgFuncp->addStmtsp(changep);
 		AstAssign* initp
 		    = new AstAssign (vscp->fileline(),
-				     aselIfNeeded(isArray, index,
+				     aselIfNeeded(isUnpackArray, index,
 						  new AstVarRef(vscp->fileline(), newvscp, true)),
-				     aselIfNeeded(isArray, index,
+				     aselIfNeeded(isUnpackArray, index,
 						  new AstVarRef(vscp->fileline(), vscp, false)));
 		m_chgFuncp->addFinalsp(initp);
 	    }
diff --git a/test_regress/t/t_detectarray_3.pl b/test_regress/t/t_detectarray_3.pl
new file mode 100755
index 000000000..0ab9fe201
--- /dev/null
+++ b/test_regress/t/t_detectarray_3.pl
@@ -0,0 +1,19 @@
+#!/usr/bin/perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you can
+# redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+
+compile (
+    verilator_flags2 => ["-Wno-UNOPTFLAT -Wno-WIDTH"]
+    );
+
+execute (
+    check_finished=>1,
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_detectarray_3.v b/test_regress/t/t_detectarray_3.v
new file mode 100644
index 000000000..932bebb89
--- /dev/null
+++ b/test_regress/t/t_detectarray_3.v
@@ -0,0 +1,39 @@
+// DESCRIPTION: Verilator: Simple test of unoptflat
+//
+// Trigger the DETECTARRAY error on packed structure.
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2014 by Jie Xu.
+
+localparam ID_MSB = 1;
+
+
+module t (/*AUTOARG*/
+   // Inputs
+   clk,
+   res
+   );
+   input clk;
+   output [8:0][8:0] res;
+
+   logic a = 1'b1;
+   logic [8:0] b [8:0];  // where the error is reported
+   logic [8:0][8:0] c;  // where the error is reported
+
+   // following just to make c as circular
+   assign c[0] = c[0] | a << 1;
+   assign b[0] = b[0] | a << 2;
+
+   assign res[0] = c[0];
+   assign res[1] = b[0];
+
+
+   always @(posedge clk or negedge clk) begin
+
+     if (res != 0) begin
+	 $write("*-* All Finished *-*\n");
+	 $finish;
+      end
+   end
+
+endmodule