diff --git a/mercurial/patch.py b/mercurial/patch.py
--- a/mercurial/patch.py
+++ b/mercurial/patch.py
@@ -2552,7 +2552,7 @@ def trydiff(repo, revs, ctx1, ctx2, modi
         elif revs and not repo.ui.quiet:
             header.append(diffline(path1, revs))
 
-        if binary and opts.git and not opts.nobinary:
+        if binary and opts.git and not opts.nobinary and not opts.text:
             text = mdiff.b85diff(content1, content2)
             if text:
                 header.append('index %s..%s' %
diff --git a/tests/test-diff-binary-file.t b/tests/test-diff-binary-file.t
--- a/tests/test-diff-binary-file.t
+++ b/tests/test-diff-binary-file.t
@@ -73,5 +73,39 @@
   literal 5
   Mc$_OqttjCF00uV!&;S4c
   
+  $ cd ..
+
+Test text mode with extended git-style diff format
+  $ hg init b
+  $ cd b
+  $ cat > writebin.py <<EOF
+  > import sys
+  > path = sys.argv[1]
+  > open(path, 'wb').write('\x00\x01\x02\x03')
+  > EOF
+  $ python writebin.py binfile.bin
+  $ hg add binfile.bin
+  $ hg ci -m 'add binfile.bin'
+
+  $ echo >> binfile.bin
+  $ hg ci -m 'change binfile.bin'
+
+  $ hg diff --git -a -r 0 -r 1
+  diff --git a/binfile.bin b/binfile.bin
+  --- a/binfile.bin
+  +++ b/binfile.bin
+  @@ -1,1 +1,1 @@
+  -\x00\x01\x02\x03 (esc)
+  \ No newline at end of file
+  +\x00\x01\x02\x03 (esc)
+
+  $ HGPLAIN=1 hg diff --git -a -r 0 -r 1
+  diff --git a/binfile.bin b/binfile.bin
+  --- a/binfile.bin
+  +++ b/binfile.bin
+  @@ -1,1 +1,1 @@
+  -\x00\x01\x02\x03 (esc)
+  \ No newline at end of file
+  +\x00\x01\x02\x03 (esc)
 
   $ cd ..