diff --git a/tools/binman/etype/blob.py b/tools/binman/etype/blob.py
index 301ac55..81756c3 100644
--- a/tools/binman/etype/blob.py
+++ b/tools/binman/etype/blob.py
@@ -66,3 +66,7 @@
 
     def GetDefaultFilename(self):
         return self._filename
+
+    def ProcessContents(self):
+        # The blob may have changed due to WriteSymbols()
+        return self.ProcessContentsUpdate(self.data)
diff --git a/tools/binman/etype/vblock.py b/tools/binman/etype/vblock.py
index f734fba..eba5351 100644
--- a/tools/binman/etype/vblock.py
+++ b/tools/binman/etype/vblock.py
@@ -49,7 +49,7 @@
             EntryArg('kernelkey', str),
             EntryArg('preamble-flags', int)])
 
-    def ObtainContents(self):
+    def GetVblock(self):
         # Join up the data files to be signed
         input_data = b''
         for entry_phandle in self.content:
@@ -76,5 +76,16 @@
         ]
         #out.Notice("Sign '%s' into %s" % (', '.join(self.value), self.label))
         stdout = tools.Run('futility', *args)
-        self.SetContents(tools.ReadFile(output_fname))
+        return tools.ReadFile(output_fname)
+
+    def ObtainContents(self):
+        data = self.GetVblock()
+        if data is False:
+            return False
+        self.SetContents(data)
         return True
+
+    def ProcessContents(self):
+        # The blob may have changed due to WriteSymbols()
+        data = self.GetVblock()
+        return self.ProcessContentsUpdate(data)
diff --git a/tools/binman/ftest.py b/tools/binman/ftest.py
index 8b928eb..7f7827b 100644
--- a/tools/binman/ftest.py
+++ b/tools/binman/ftest.py
@@ -1638,15 +1638,37 @@
                       str(e.exception))
 
     def _HandleVblockCommand(self, pipe_list):
-        """Fake calls to the futility utility"""
+        """Fake calls to the futility utility
+
+        The expected pipe is:
+
+           [('futility', 'vbutil_firmware', '--vblock',
+             'vblock.vblock', '--keyblock', 'devkeys/firmware.keyblock',
+             '--signprivate', 'devkeys/firmware_data_key.vbprivk',
+             '--version', '1', '--fv', 'input.vblock', '--kernelkey',
+             'devkeys/kernel_subkey.vbpubk', '--flags', '1')]
+
+        This writes to the output file (here, 'vblock.vblock'). If
+        self._hash_data is False, it writes VBLOCK_DATA, else it writes a hash
+        of the input data (here, 'input.vblock').
+        """
         if pipe_list[0][0] == 'futility':
             fname = pipe_list[0][3]
             with open(fname, 'wb') as fd:
-                fd.write(VBLOCK_DATA)
+                if self._hash_data:
+                    infile = pipe_list[0][11]
+                    m = hashlib.sha256()
+                    data = tools.ReadFile(infile)
+                    m.update(data)
+                    fd.write(m.digest())
+                else:
+                    fd.write(VBLOCK_DATA)
+
             return command.CommandResult()
 
     def testVblock(self):
         """Test for the Chromium OS Verified Boot Block"""
+        self._hash_data = False
         command.test_result = self._HandleVblockCommand
         entry_args = {
             'keydir': 'devkeys',
@@ -1677,6 +1699,29 @@
         self.assertIn("Node '/binman/vblock': Cannot find entry for node "
                       "'other'", str(e.exception))
 
+    def testVblockContent(self):
+        """Test that the vblock signs the right data"""
+        self._hash_data = True
+        command.test_result = self._HandleVblockCommand
+        entry_args = {
+            'keydir': 'devkeys',
+        }
+        data = self._DoReadFileDtb(
+            '189_vblock_content.dts', use_real_dtb=True, update_dtb=True,
+            entry_args=entry_args)[0]
+        hashlen = 32  # SHA256 hash is 32 bytes
+        self.assertEqual(U_BOOT_DATA, data[:len(U_BOOT_DATA)])
+        hashval = data[-hashlen:]
+        dtb = data[len(U_BOOT_DATA):-hashlen]
+
+        expected_data = U_BOOT_DATA + dtb
+
+        # The hashval should be a hash of the dtb
+        m = hashlib.sha256()
+        m.update(expected_data)
+        expected_hashval = m.digest()
+        self.assertEqual(expected_hashval, hashval)
+
     def testTpl(self):
         """Test that an image with TPL and its device tree can be created"""
         # ELF file with a '__bss_size' symbol
diff --git a/tools/binman/image.py b/tools/binman/image.py
index 3c2fe5e..e949435 100644
--- a/tools/binman/image.py
+++ b/tools/binman/image.py
@@ -136,12 +136,7 @@
         Returns:
             True if the new data size is OK, False if expansion is needed
         """
-        sizes_ok = True
-        for entry in self._entries.values():
-            if not entry.ProcessContents():
-                sizes_ok = False
-                tout.Debug("Entry '%s' size change" % self._node.path)
-        return sizes_ok
+        return super().ProcessContents()
 
     def WriteSymbols(self):
         """Write symbol values into binary files for access at run time"""
diff --git a/tools/binman/test/189_vblock_content.dts b/tools/binman/test/189_vblock_content.dts
new file mode 100644
index 0000000..dcc7444
--- /dev/null
+++ b/tools/binman/test/189_vblock_content.dts
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0+
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	binman {
+		u_boot: u-boot {
+		};
+
+		dtb: u-boot-dtb {
+		};
+
+		/*
+		 * Put the vblock after the dtb so that the dtb is updated
+		 * before the vblock reads its data. At present binman does not
+		 * understand dependencies between entries, but simply
+		 * iterates again when it thinks something needs to be
+		 * recalculated.
+		 */
+		vblock {
+			content = <&u_boot &dtb>;
+			keyblock = "firmware.keyblock";
+			signprivate = "firmware_data_key.vbprivk";
+			version = <1>;
+			kernelkey = "kernel_subkey.vbpubk";
+			preamble-flags = <1>;
+		};
+	};
+};