diff --git a/src/if_cscope.c b/src/if_cscope.c
index 168b3e49e3..4bf28ad1d1 100644
--- a/src/if_cscope.c
+++ b/src/if_cscope.c
@@ -677,7 +677,7 @@ cs_cnt_matches(int idx)
 {
     char *stok;
     char *buf;
-    int nlines;
+    int nlines = 0;
 
     buf = (char *)alloc(CSREAD_BUFSIZE);
     if (buf == NULL)
@@ -700,7 +700,10 @@ cs_cnt_matches(int idx)
 	 * cscope will output error messages before the number-of-lines output.
 	 * Display/discard any output that doesn't match what we want.
 	 * Accept "\S*cscope: X lines", also matches "mlcscope".
+	 * Bail out for the "Unable to search" error.
 	 */
+	if (strstr((const char *)buf, "Unable to search database") != NULL)
+	    break;
 	if ((stok = strtok(buf, (const char *)" ")) == NULL)
 	    continue;
 	if (strstr((const char *)stok, "cscope:") == NULL)
diff --git a/src/terminal.c b/src/terminal.c
index 1da0027132..f26d1e42ce 100644
--- a/src/terminal.c
+++ b/src/terminal.c
@@ -649,6 +649,29 @@ free_terminal(buf_T *buf)
 	in_terminal_loop = NULL;
 }
 
+/*
+ * Get the part that is connected to the tty. Normally this is PART_IN, but
+ * when writing buffer lines to the job it can be another.  This makes it
+ * possible to do "1,5term vim -".
+ */
+    static ch_part_T
+get_tty_part(term_T *term)
+{
+#ifdef UNIX
+    ch_part_T	parts[3] = {PART_IN, PART_OUT, PART_ERR};
+    int		i;
+
+    for (i = 0; i < 3; ++i)
+    {
+	int fd = term->tl_job->jv_channel->ch_part[parts[i]].ch_fd;
+
+	if (isatty(fd))
+	    return parts[i];
+    }
+#endif
+    return PART_IN;
+}
+
 /*
  * Write job output "msg[len]" to the vterm.
  */
@@ -656,9 +679,21 @@ free_terminal(buf_T *buf)
 term_write_job_output(term_T *term, char_u *msg, size_t len)
 {
     VTerm	*vterm = term->tl_vterm;
+    size_t	prevlen = vterm_output_get_buffer_current(vterm);
 
     vterm_input_write(vterm, (char *)msg, len);
 
+    /* flush vterm buffer when vterm responded to control sequence */
+    if (prevlen != vterm_output_get_buffer_current(vterm))
+    {
+	char   buf[KEY_BUF_LEN];
+	size_t curlen = vterm_output_read(vterm, buf, KEY_BUF_LEN);
+
+	if (curlen > 0)
+	    channel_send(term->tl_job->jv_channel, get_tty_part(term),
+					     (char_u *)buf, (int)curlen, NULL);
+    }
+
     /* this invokes the damage callbacks */
     vterm_screen_flush_damage(vterm_obtain_screen(vterm));
 }
@@ -1243,29 +1278,6 @@ term_vgetc()
     return c;
 }
 
-/*
- * Get the part that is connected to the tty. Normally this is PART_IN, but
- * when writing buffer lines to the job it can be another.  This makes it
- * possible to do "1,5term vim -".
- */
-    static ch_part_T
-get_tty_part(term_T *term)
-{
-#ifdef UNIX
-    ch_part_T	parts[3] = {PART_IN, PART_OUT, PART_ERR};
-    int		i;
-
-    for (i = 0; i < 3; ++i)
-    {
-	int fd = term->tl_job->jv_channel->ch_part[parts[i]].ch_fd;
-
-	if (isatty(fd))
-	    return parts[i];
-    }
-#endif
-    return PART_IN;
-}
-
 /*
  * Send keys to terminal.
  * Return FAIL when the key needs to be handled in Normal mode.
diff --git a/src/testdir/test_search.vim b/src/testdir/test_search.vim
index 9b96b49fde..130562fc5e 100644
--- a/src/testdir/test_search.vim
+++ b/src/testdir/test_search.vim
@@ -619,6 +619,8 @@ func Test_search_cmdline_incsearch_highlight_attr()
   let buf = term_start([GetVimProg(), '--clean', '-c', 'set noswapfile', 'Xsearch.txt'], {'term_rows': 3})
 
   call WaitFor({-> lines == [term_getline(buf, 1), term_getline(buf, 2)] })
+  " wait for vim to complete initialization
+  call term_wait(buf)
 
   " Get attr of normal(a0), incsearch(a1), hlsearch(a2) highlight
   call term_sendkeys(buf, ":set incsearch hlsearch\<cr>")
diff --git a/src/testdir/test_terminal.vim b/src/testdir/test_terminal.vim
index 89d086ced2..20c21ae143 100644
--- a/src/testdir/test_terminal.vim
+++ b/src/testdir/test_terminal.vim
@@ -811,3 +811,26 @@ func Test_terminal_term_start_empty_command()
   let cmd = "call term_start(0, {'curwin' : 1, 'term_finish' : 'close'})"
   call assert_fails(cmd, 'E474')
 endfunc
+
+func Test_terminal_response_to_control_sequence()
+  if !has('unix')
+    return
+  endif
+
+  let buf = Run_shell_in_terminal({})
+  call term_wait(buf)
+
+  call term_sendkeys(buf, s:python . " -c 'import sys;sys.stdout.write(\"\\x1b[6n\")'\<cr>")
+  " wait for the response of control sequence from libvterm (and send it to tty)
+  call term_wait(buf, 100)
+  " wait for output from tty to display
+  call term_wait(buf)
+  call assert_match(';\d\+R', term_getline(buf, 2))
+
+  call term_sendkeys(buf, "\<c-c>")
+  call term_wait(buf)
+  call Stop_shell_in_terminal(buf)
+
+  exe buf . 'bwipe'
+  unlet g:job
+endfunc
diff --git a/src/testdir/test_undo.vim b/src/testdir/test_undo.vim
index b7235867b9..cc3cceb1ae 100644
--- a/src/testdir/test_undo.vim
+++ b/src/testdir/test_undo.vim
@@ -359,3 +359,47 @@ func Test_undo_append()
   norm o
   quit
 endfunc
+
+func Test_undo_0()
+  new
+  set ul=100
+  normal i1
+  undo
+  normal i2
+  undo
+  normal i3
+
+  undo 0
+  let d = undotree()
+  call assert_equal('', getline(1))
+  call assert_equal(0, d.seq_cur)
+
+  redo
+  let d = undotree()
+  call assert_equal('3', getline(1))
+  call assert_equal(3, d.seq_cur)
+
+  undo 2
+  undo 0
+  let d = undotree()
+  call assert_equal('', getline(1))
+  call assert_equal(0, d.seq_cur)
+
+  redo
+  let d = undotree()
+  call assert_equal('2', getline(1))
+  call assert_equal(2, d.seq_cur)
+
+  undo 1
+  undo 0
+  let d = undotree()
+  call assert_equal('', getline(1))
+  call assert_equal(0, d.seq_cur)
+
+  redo
+  let d = undotree()
+  call assert_equal('1', getline(1))
+  call assert_equal(1, d.seq_cur)
+
+  bwipe!
+endfunc
diff --git a/src/undo.c b/src/undo.c
index ae4b4a44c9..0b7656a40f 100644
--- a/src/undo.c
+++ b/src/undo.c
@@ -2272,7 +2272,7 @@ undo_time(
     long	    closest_start;
     long	    closest_seq = 0;
     long	    val;
-    u_header_T	    *uhp;
+    u_header_T	    *uhp = NULL;
     u_header_T	    *last;
     int		    mark;
     int		    nomark;
@@ -2295,14 +2295,7 @@ undo_time(
      * Init "closest" to a value we can't reach. */
     if (absolute)
     {
-	if (step == 0)
-	{
-	    /* target 0 does not exist, got to 1 and above it. */
-	    target = 1;
-	    above = TRUE;
-	}
-	else
-	    target = step;
+	target = step;
 	closest = -1;
     }
     else
@@ -2369,6 +2362,10 @@ undo_time(
     closest_start = closest;
     closest_seq = curbuf->b_u_seq_cur;
 
+    /* When "target" is 0; Back to origin. */
+    if (target == 0)
+	goto found;
+
     /*
      * May do this twice:
      * 1. Search for "target", update "closest" to the best match found.
@@ -2494,8 +2491,9 @@ undo_time(
 	    above = TRUE;	/* stop above the header */
     }
 
+found:
     /* If we found it: Follow the path to go to where we want to be. */
-    if (uhp != NULL)
+    if (uhp != NULL || target == 0)
     {
 	/*
 	 * First go up the tree as much as needed.
@@ -2510,87 +2508,93 @@ undo_time(
 		uhp = curbuf->b_u_newhead;
 	    else
 		uhp = uhp->uh_next.ptr;
-	    if (uhp == NULL || uhp->uh_walk != mark
+	    if (uhp == NULL || (target > 0 && uhp->uh_walk != mark)
 					 || (uhp->uh_seq == target && !above))
 		break;
 	    curbuf->b_u_curhead = uhp;
 	    u_undoredo(TRUE);
-	    uhp->uh_walk = nomark;	/* don't go back down here */
+	    if (target > 0)
+		uhp->uh_walk = nomark;	/* don't go back down here */
 	}
 
-	/*
-	 * And now go down the tree (redo), branching off where needed.
-	 */
-	while (!got_int)
+	/* When back to origin, redo is not needed. */
+	if (target > 0)
 	{
-	    /* Do the change warning now, for the same reason as above. */
-	    change_warning(0);
+	    /*
+	     * And now go down the tree (redo), branching off where needed.
+	     */
+	    while (!got_int)
+	    {
+		/* Do the change warning now, for the same reason as above. */
+		change_warning(0);
 
-	    uhp = curbuf->b_u_curhead;
-	    if (uhp == NULL)
-		break;
+		uhp = curbuf->b_u_curhead;
+		if (uhp == NULL)
+		    break;
 
-	    /* Go back to the first branch with a mark. */
-	    while (uhp->uh_alt_prev.ptr != NULL
+		/* Go back to the first branch with a mark. */
+		while (uhp->uh_alt_prev.ptr != NULL
 				     && uhp->uh_alt_prev.ptr->uh_walk == mark)
-		uhp = uhp->uh_alt_prev.ptr;
-
-	    /* Find the last branch with a mark, that's the one. */
-	    last = uhp;
-	    while (last->uh_alt_next.ptr != NULL
-				    && last->uh_alt_next.ptr->uh_walk == mark)
-		last = last->uh_alt_next.ptr;
-	    if (last != uhp)
-	    {
-		/* Make the used branch the first entry in the list of
-		 * alternatives to make "u" and CTRL-R take this branch. */
-		while (uhp->uh_alt_prev.ptr != NULL)
 		    uhp = uhp->uh_alt_prev.ptr;
-		if (last->uh_alt_next.ptr != NULL)
-		    last->uh_alt_next.ptr->uh_alt_prev.ptr =
+
+		/* Find the last branch with a mark, that's the one. */
+		last = uhp;
+		while (last->uh_alt_next.ptr != NULL
+				    && last->uh_alt_next.ptr->uh_walk == mark)
+		    last = last->uh_alt_next.ptr;
+		if (last != uhp)
+		{
+		    /* Make the used branch the first entry in the list of
+		     * alternatives to make "u" and CTRL-R take this branch. */
+		    while (uhp->uh_alt_prev.ptr != NULL)
+			uhp = uhp->uh_alt_prev.ptr;
+		    if (last->uh_alt_next.ptr != NULL)
+			last->uh_alt_next.ptr->uh_alt_prev.ptr =
 							last->uh_alt_prev.ptr;
-		last->uh_alt_prev.ptr->uh_alt_next.ptr = last->uh_alt_next.ptr;
-		last->uh_alt_prev.ptr = NULL;
-		last->uh_alt_next.ptr = uhp;
-		uhp->uh_alt_prev.ptr = last;
+		    last->uh_alt_prev.ptr->uh_alt_next.ptr =
+							last->uh_alt_next.ptr;
+		    last->uh_alt_prev.ptr = NULL;
+		    last->uh_alt_next.ptr = uhp;
+		    uhp->uh_alt_prev.ptr = last;
 
-		if (curbuf->b_u_oldhead == uhp)
-		    curbuf->b_u_oldhead = last;
-		uhp = last;
-		if (uhp->uh_next.ptr != NULL)
-		    uhp->uh_next.ptr->uh_prev.ptr = uhp;
-	    }
-	    curbuf->b_u_curhead = uhp;
+		    if (curbuf->b_u_oldhead == uhp)
+			curbuf->b_u_oldhead = last;
+		    uhp = last;
+		    if (uhp->uh_next.ptr != NULL)
+			uhp->uh_next.ptr->uh_prev.ptr = uhp;
+		}
+		curbuf->b_u_curhead = uhp;
 
-	    if (uhp->uh_walk != mark)
-		break;	    /* must have reached the target */
+		if (uhp->uh_walk != mark)
+		    break;	    /* must have reached the target */
 
-	    /* Stop when going backwards in time and didn't find the exact
-	     * header we were looking for. */
-	    if (uhp->uh_seq == target && above)
-	    {
-		curbuf->b_u_seq_cur = target - 1;
-		break;
-	    }
+		/* Stop when going backwards in time and didn't find the exact
+		 * header we were looking for. */
+		if (uhp->uh_seq == target && above)
+		{
+		    curbuf->b_u_seq_cur = target - 1;
+		    break;
+		}
 
-	    u_undoredo(FALSE);
+		u_undoredo(FALSE);
 
-	    /* Advance "curhead" to below the header we last used.  If it
-	     * becomes NULL then we need to set "newhead" to this leaf. */
-	    if (uhp->uh_prev.ptr == NULL)
-		curbuf->b_u_newhead = uhp;
-	    curbuf->b_u_curhead = uhp->uh_prev.ptr;
-	    did_undo = FALSE;
+		/* Advance "curhead" to below the header we last used.  If it
+		 * becomes NULL then we need to set "newhead" to this leaf. */
+		if (uhp->uh_prev.ptr == NULL)
+		    curbuf->b_u_newhead = uhp;
+		curbuf->b_u_curhead = uhp->uh_prev.ptr;
+		did_undo = FALSE;
 
-	    if (uhp->uh_seq == target)	/* found it! */
-		break;
+		if (uhp->uh_seq == target)	/* found it! */
+		    break;
 
-	    uhp = uhp->uh_prev.ptr;
-	    if (uhp == NULL || uhp->uh_walk != mark)
-	    {
-		/* Need to redo more but can't find it... */
-		internal_error("undo_time()");
-		break;
+		uhp = uhp->uh_prev.ptr;
+		if (uhp == NULL || uhp->uh_walk != mark)
+		{
+		    /* Need to redo more but can't find it... */
+		    internal_error("undo_time()");
+		    break;
+		}
 	    }
 	}
     }
diff --git a/src/version.c b/src/version.c
index 98800d228f..ee2f791c12 100644
--- a/src/version.c
+++ b/src/version.c
@@ -786,6 +786,14 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1442,
+/**/
+    1441,
+/**/
+    1440,
+/**/
+    1439,
 /**/
     1438,
 /**/