diff --git a/tools/binman/control.py b/tools/binman/control.py
index c3f358d..22e3e30 100644
--- a/tools/binman/control.py
+++ b/tools/binman/control.py
@@ -333,7 +333,7 @@
             break
         image.ResetForPack()
     if not sizes_ok:
-        image.Raise('Entries expanded after packing (tried %s passes)' %
+        image.Raise('Entries changed size after packing (tried %s passes)' %
                     passes)
 
     image.WriteSymbols()
diff --git a/tools/binman/entry.py b/tools/binman/entry.py
index 8dacc61..90192c1 100644
--- a/tools/binman/entry.py
+++ b/tools/binman/entry.py
@@ -285,16 +285,26 @@
         """
         size_ok = True
         new_size = len(data)
-        if state.AllowEntryExpansion():
+        if state.AllowEntryExpansion() and new_size > self.contents_size:
+            # self.data will indicate the new size needed
+            size_ok = False
+        elif state.AllowEntryContraction() and new_size < self.contents_size:
+            size_ok = False
+
+        # If not allowed to change, try to deal with it or give up
+        if size_ok:
             if new_size > self.contents_size:
-                tout.Debug("Entry '%s' size change from %s to %s" % (
-                    self._node.path, ToHex(self.contents_size),
-                    ToHex(new_size)))
-                # self.data will indicate the new size needed
-                size_ok = False
-        elif new_size != self.contents_size:
-            self.Raise('Cannot update entry size from %d to %d' %
-                       (self.contents_size, new_size))
+                self.Raise('Cannot update entry size from %d to %d' %
+                        (self.contents_size, new_size))
+
+            # Don't let the data shrink. Pad it if necessary
+            if size_ok and new_size < self.contents_size:
+                data += tools.GetBytes(0, self.contents_size - new_size)
+
+        if not size_ok:
+            tout.Debug("Entry '%s' size change from %s to %s" % (
+                self._node.path, ToHex(self.contents_size),
+                ToHex(new_size)))
         self.SetContents(data)
         return size_ok
 
diff --git a/tools/binman/ftest.py b/tools/binman/ftest.py
index f8568d7..11155ce 100644
--- a/tools/binman/ftest.py
+++ b/tools/binman/ftest.py
@@ -2143,7 +2143,7 @@
         """Test expanding an entry after it is packed, twice"""
         with self.assertRaises(ValueError) as e:
             self._DoReadFile('122_entry_expand_twice.dts')
-        self.assertIn("Image '/binman': Entries expanded after packing",
+        self.assertIn("Image '/binman': Entries changed size after packing",
                       str(e.exception))
 
     def testEntryExpandSection(self):
@@ -2952,6 +2952,29 @@
         self.assertIn('Entry data size does not match, but allow-repack is not present for this image',
                       str(e.exception))
 
+    def testEntryShrink(self):
+        """Test contracting an entry after it is packed"""
+        try:
+            state.SetAllowEntryContraction(True)
+            data = self._DoReadFileDtb('140_entry_shrink.dts',
+                                       update_dtb=True)[0]
+        finally:
+            state.SetAllowEntryContraction(False)
+        self.assertEqual(b'a', data[:1])
+        self.assertEqual(U_BOOT_DATA, data[1:1 + len(U_BOOT_DATA)])
+        self.assertEqual(b'a', data[-1:])
+
+    def testEntryShrinkFail(self):
+        """Test not being allowed to contract an entry after it is packed"""
+        data = self._DoReadFileDtb('140_entry_shrink.dts', update_dtb=True)[0]
+
+        # In this case there is a spare byte at the end of the data. The size of
+        # the contents is only 1 byte but we still have the size before it
+        # shrunk.
+        self.assertEqual(b'a\0', data[:2])
+        self.assertEqual(U_BOOT_DATA, data[2:2 + len(U_BOOT_DATA)])
+        self.assertEqual(b'a\0', data[-2:])
+
 
 if __name__ == "__main__":
     unittest.main()
diff --git a/tools/binman/state.py b/tools/binman/state.py
index 6553615..f22cc82 100644
--- a/tools/binman/state.py
+++ b/tools/binman/state.py
@@ -42,6 +42,14 @@
 # Entry.ProcessContentsUpdate()
 allow_entry_expansion = True
 
+# Don't allow entries to contract after they have been packed. Instead just
+# leave some wasted space. If allowed, this is detected and forces a re-pack,
+# but may result in entries that oscillate in size, thus causing a pack error.
+# An example is a compressed device tree where the original offset values
+# result in a larger compressed size than the new ones, but then after updating
+# to the new ones, the compressed size increases, etc.
+allow_entry_contraction = False
+
 def GetFdtForEtype(etype):
     """Get the Fdt object for a particular device-tree entry
 
@@ -346,3 +354,22 @@
             raised
     """
     return allow_entry_expansion
+
+def SetAllowEntryContraction(allow):
+    """Set whether post-pack contraction of entries is allowed
+
+    Args:
+       allow: True to allow contraction, False to raise an exception
+    """
+    global allow_entry_contraction
+
+    allow_entry_contraction = allow
+
+def AllowEntryContraction():
+    """Check whether post-pack contraction of entries is allowed
+
+    Returns:
+        True if contraction should be allowed, False if an exception should be
+            raised
+    """
+    return allow_entry_contraction
diff --git a/tools/binman/test/140_entry_shrink.dts b/tools/binman/test/140_entry_shrink.dts
new file mode 100644
index 0000000..b750d63
--- /dev/null
+++ b/tools/binman/test/140_entry_shrink.dts
@@ -0,0 +1,20 @@
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	binman {
+		_testing {
+			bad-shrink-contents;
+		};
+
+		u-boot {
+		};
+
+		_testing2 {
+			type = "_testing";
+			bad-shrink-contents;
+		};
+	};
+};