diff --git a/include/jtag/part.h b/include/jtag/part.h
index 5941c06d..917200f1 100644
--- a/include/jtag/part.h
+++ b/include/jtag/part.h
@@ -40,6 +40,7 @@ struct part {
 	instruction *active_instruction;
 	int boundary_length;
 	bsbit **bsbits;
+	tap_register *idr;
 	tap_register *bsr;
 	tap_register *prev_bsr;
 };
diff --git a/jtag/src/part/parse.c b/jtag/src/part/parse.c
index 64658a81..5e809189 100644
--- a/jtag/src/part/parse.c
+++ b/jtag/src/part/parse.c
@@ -38,7 +38,7 @@ get_token( char *buf )
 }
 
 part *
-read_part( FILE *f )
+read_part( FILE *f, tap_register *idr )
 {
 	int line = 0;
 	part *part;
@@ -52,6 +52,8 @@ read_part( FILE *f )
 		return NULL;
 	}
 
+	part->idr = register_duplicate( idr );
+
 	for (;;) {
 		char *t;
 		char buf[1024];
diff --git a/jtag/src/part/part.c b/jtag/src/part/part.c
index a66a4876..2386159d 100644
--- a/jtag/src/part/part.c
+++ b/jtag/src/part/part.c
@@ -42,6 +42,7 @@ part_alloc( void )
 	p->active_instruction = NULL;
 	p->boundary_length = 0;
 	p->bsbits = NULL;
+	p->idr = NULL;
 	p->bsr = NULL;
 	p->prev_bsr = NULL;
 
@@ -75,6 +76,9 @@ part_free( part *p )
 		bsbit_free( p->bsbits[i] );
 	free( p->bsbits );
 
+	/* idr */
+	register_free( p->idr );
+
 	/* bsr */
 	register_free( p->bsr );
 	register_free( p->prev_bsr );