diff --git a/src/buffer.c b/src/buffer.c
index 6d44fa7..c947901 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -502,6 +502,7 @@
     buf->b_start_eol = TRUE;
 #ifdef FEAT_MBYTE
     buf->b_p_bomb = FALSE;
+    buf->b_start_bomb = FALSE;
 #endif
     buf->b_ml.ml_mfp = NULL;
     buf->b_ml.ml_flags = ML_EMPTY;		/* empty buffer */
diff --git a/src/fileio.c b/src/fileio.c
index 3f094d4..801caba 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -654,6 +654,7 @@
 	curbuf->b_start_eol = TRUE;
 #ifdef FEAT_MBYTE
 	curbuf->b_p_bomb = FALSE;
+	curbuf->b_start_bomb = FALSE;
 #endif
     }
 
@@ -912,7 +913,10 @@
 	file_rewind = FALSE;
 #ifdef FEAT_MBYTE
 	if (set_options)
+	{
 	    curbuf->b_p_bomb = FALSE;
+	    curbuf->b_start_bomb = FALSE;
+	}
 	conv_error = 0;
 #endif
     }
@@ -1361,7 +1365,10 @@
 		    size -= blen;
 		    mch_memmove(ptr, ptr + blen, (size_t)size);
 		    if (set_options)
+		    {
 			curbuf->b_p_bomb = TRUE;
+			curbuf->b_start_bomb = TRUE;
+		    }
 		}
 
 		if (fio_flags == FIO_UCSBOM)
diff --git a/src/option.c b/src/option.c
index 68a779f..d02605c 100644
--- a/src/option.c
+++ b/src/option.c
@@ -7118,6 +7118,11 @@
     /* when 'endofline' is changed, redraw the window title */
     else if ((int *)varp == &curbuf->b_p_eol)
 	need_maketitle = TRUE;
+#ifdef FEAT_MBYTE
+    /* when 'bomb' is changed, redraw the window title */
+    else if ((int *)varp == &curbuf->b_p_bomb)
+	need_maketitle = TRUE;
+#endif
 #endif
 
     /* when 'bin' is set also set some other options */
@@ -10604,6 +10609,8 @@
     buf->b_start_ffc = *buf->b_p_ff;
     buf->b_start_eol = buf->b_p_eol;
 #ifdef FEAT_MBYTE
+    buf->b_start_bomb = buf->b_p_bomb;
+
     /* Only use free/alloc when necessary, they take time. */
     if (buf->b_start_fenc == NULL
 			     || STRCMP(buf->b_start_fenc, buf->b_p_fenc) != 0)
@@ -10617,7 +10624,8 @@
 /*
  * Return TRUE if 'fileformat' and/or 'fileencoding' has a different value
  * from when editing started (save_file_ff() called).
- * Also when 'endofline' was changed and 'binary' is set.
+ * Also when 'endofline' was changed and 'binary' is set, or when 'bomb' was
+ * changed and 'binary' is not set.
  * Don't consider a new, empty buffer to be changed.
  */
     int
@@ -10636,6 +10644,8 @@
     if (buf->b_p_bin && buf->b_start_eol != buf->b_p_eol)
 	return TRUE;
 #ifdef FEAT_MBYTE
+    if (!buf->b_p_bin && buf->b_start_bomb != buf->b_p_bomb)
+	return TRUE;
     if (buf->b_start_fenc == NULL)
 	return (*buf->b_p_fenc != NUL);
     return (STRCMP(buf->b_start_fenc, buf->b_p_fenc) != 0);
diff --git a/src/structs.h b/src/structs.h
index c85fc05..880f0b0 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -1453,6 +1453,7 @@
 #ifdef FEAT_MBYTE
     char_u	*b_start_fenc;	/* 'fileencoding' when edit started or NULL */
     int		b_bad_char;	/* "++bad=" argument when edit started or 0 */
+    int		b_start_bomb;	/* 'bomb' when it was read */
 #endif
 
 #ifdef FEAT_EVAL
diff --git a/src/version.c b/src/version.c
index 4bbf44a..7933223 100644
--- a/src/version.c
+++ b/src/version.c
@@ -667,6 +667,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    66,
+/**/
     65,
 /**/
     64,