diff --git a/src/blob.c b/src/blob.c
index cbd26b9..fb40a57 100644
--- a/src/blob.c
+++ b/src/blob.c
@@ -63,6 +63,7 @@
     int	    ret = OK;
 
     to->v_type = VAR_BLOB;
+    to->v_lock = 0;
     if (from->vval.v_blob == NULL)
 	to->vval.v_blob = NULL;
     else if (rettv_blob_alloc(to) == FAIL)
diff --git a/src/testdir/test_blob.vim b/src/testdir/test_blob.vim
index b01e11b..273465d 100644
--- a/src/testdir/test_blob.vim
+++ b/src/testdir/test_blob.vim
@@ -71,6 +71,10 @@
   call assert_fails('let b .= "xx"', 'E734:')
   call assert_fails('let b += "xx"', 'E734:')
   call assert_fails('let b[1:1] .= 0z55', 'E734:')
+
+  let l = [0z12]
+  let m = deepcopy(l)
+  let m[0] = 0z34	" E742 or E741 should not occur.
 endfunc
 
 func Test_blob_get_range()
diff --git a/src/version.c b/src/version.c
index b5504b1..9825924 100644
--- a/src/version.c
+++ b/src/version.c
@@ -778,6 +778,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1671,
+/**/
     1670,
 /**/
     1669,