diff --git a/common/subprocess.cc b/common/subprocess.cc
index 36655c7..5206503 100644
--- a/common/subprocess.cc
+++ b/common/subprocess.cc
@@ -95,6 +95,7 @@
   proc->RedirectUsingPipe(STDOUT_FILENO, false);
   proc->SetPreExecCallback(base::Bind(&SetupChild, env, flags));
 
+  LOG(INFO) << "Running \"" << base::JoinString(cmd, " ") << "\"";
   return proc->Start();
 }
 
@@ -229,22 +230,20 @@
 
 bool Subprocess::SynchronousExec(const vector<string>& cmd,
                                  int* return_code,
-                                 string* stdout) {
-  // The default for SynchronousExec is to use kSearchPath since the code relies
-  // on that.
-  return SynchronousExecFlags(
-      cmd, kRedirectStderrToStdout | kSearchPath, return_code, stdout);
+                                 string* stdout,
+                                 string* stderr) {
+  // The default for |SynchronousExec| is to use |kSearchPath| since the code
+  // relies on that.
+  return SynchronousExecFlags(cmd, kSearchPath, return_code, stdout, stderr);
 }
 
 bool Subprocess::SynchronousExecFlags(const vector<string>& cmd,
                                       uint32_t flags,
                                       int* return_code,
-                                      string* stdout) {
+                                      string* stdout,
+                                      string* stderr) {
   brillo::ProcessImpl proc;
-  // It doesn't make sense to redirect some pipes in the synchronous case
-  // because we won't be reading on our end, so we don't expose the output_pipes
-  // in this case.
-  if (!LaunchProcess(cmd, flags, {}, &proc)) {
+  if (!LaunchProcess(cmd, flags, {STDERR_FILENO}, &proc)) {
     LOG(ERROR) << "Failed to launch subprocess";
     return false;
   }
@@ -252,21 +251,39 @@
   if (stdout) {
     stdout->clear();
   }
+  if (stderr) {
+    stderr->clear();
+  }
 
-  int fd = proc.GetPipe(STDOUT_FILENO);
+  // Read from both stdout and stderr individually.
+  int stdout_fd = proc.GetPipe(STDOUT_FILENO);
+  int stderr_fd = proc.GetPipe(STDERR_FILENO);
   vector<char> buffer(32 * 1024);
-  while (true) {
-    int rc = HANDLE_EINTR(read(fd, buffer.data(), buffer.size()));
-    if (rc < 0) {
-      PLOG(ERROR) << "Reading from child's output";
-      break;
-    } else if (rc == 0) {
-      break;
-    } else {
-      if (stdout)
+  bool stdout_closed = false, stderr_closed = false;
+  while (!stdout_closed || !stderr_closed) {
+    if (!stdout_closed) {
+      int rc = HANDLE_EINTR(read(stdout_fd, buffer.data(), buffer.size()));
+      if (rc <= 0) {
+        stdout_closed = true;
+        if (rc < 0)
+          PLOG(ERROR) << "Reading from child's stdout";
+      } else if (stdout != nullptr) {
         stdout->append(buffer.data(), rc);
+      }
+    }
+
+    if (!stderr_closed) {
+      int rc = HANDLE_EINTR(read(stderr_fd, buffer.data(), buffer.size()));
+      if (rc <= 0) {
+        stderr_closed = true;
+        if (rc < 0)
+          PLOG(ERROR) << "Reading from child's stderr";
+      } else if (stderr != nullptr) {
+        stderr->append(buffer.data(), rc);
+      }
     }
   }
+
   // At this point, the subprocess already closed the output, so we only need to
   // wait for it to finish.
   int proc_return_code = proc.Wait();
diff --git a/common/subprocess.h b/common/subprocess.h
index bac9e48..3eda8d5 100644
--- a/common/subprocess.h
+++ b/common/subprocess.h
@@ -88,14 +88,16 @@
 
   // Executes a command synchronously. Returns true on success. If |stdout| is
   // non-null, the process output is stored in it, otherwise the output is
-  // logged. Note that stderr is redirected to stdout.
+  // logged.
   static bool SynchronousExec(const std::vector<std::string>& cmd,
                               int* return_code,
-                              std::string* stdout);
+                              std::string* stdout,
+                              std::string* stderr);
   static bool SynchronousExecFlags(const std::vector<std::string>& cmd,
                                    uint32_t flags,
                                    int* return_code,
-                                   std::string* stdout);
+                                   std::string* stdout,
+                                   std::string* stderr);
 
   // Gets the one instance.
   static Subprocess& Get() { return *subprocess_singleton_; }
diff --git a/common/subprocess_unittest.cc b/common/subprocess_unittest.cc
index 104ef41..8dbaa0b 100644
--- a/common/subprocess_unittest.cc
+++ b/common/subprocess_unittest.cc
@@ -193,7 +193,7 @@
 TEST_F(SubprocessTest, SynchronousTrueSearchsOnPath) {
   int rc = -1;
   EXPECT_TRUE(Subprocess::SynchronousExecFlags(
-      {"true"}, Subprocess::kSearchPath, &rc, nullptr));
+      {"true"}, Subprocess::kSearchPath, &rc, nullptr, nullptr));
   EXPECT_EQ(0, rc);
 }
 
@@ -201,16 +201,17 @@
   vector<string> cmd = {
       kBinPath "/sh", "-c", "echo -n stdout-here; echo -n stderr-there >&2"};
   int rc = -1;
-  string stdout;
-  ASSERT_TRUE(Subprocess::SynchronousExec(cmd, &rc, &stdout));
+  string stdout, stderr;
+  ASSERT_TRUE(Subprocess::SynchronousExec(cmd, &rc, &stdout, &stderr));
   EXPECT_EQ(0, rc);
-  EXPECT_EQ("stdout-herestderr-there", stdout);
+  EXPECT_EQ("stdout-here", stdout);
+  EXPECT_EQ("stderr-there", stderr);
 }
 
 TEST_F(SubprocessTest, SynchronousEchoNoOutputTest) {
   int rc = -1;
   ASSERT_TRUE(Subprocess::SynchronousExec(
-      {kBinPath "/sh", "-c", "echo test"}, &rc, nullptr));
+      {kBinPath "/sh", "-c", "echo test"}, &rc, nullptr, nullptr));
   EXPECT_EQ(0, rc);
 }
 
diff --git a/hardware_chromeos.cc b/hardware_chromeos.cc
index dd21c1b..de1d7c0 100644
--- a/hardware_chromeos.cc
+++ b/hardware_chromeos.cc
@@ -87,14 +87,16 @@
 // shell command. Returns true on success.
 int GetVpdValue(string key, string* result) {
   int exit_code = 0;
-  string value;
+  string value, error;
   vector<string> cmd = {"vpd_get_value", key};
   if (!chromeos_update_engine::Subprocess::SynchronousExec(
-          cmd, &exit_code, &value) ||
+          cmd, &exit_code, &value, &error) ||
       exit_code) {
     LOG(ERROR) << "Failed to get vpd key for " << value
-               << " with exit code: " << exit_code;
+               << " with exit code: " << exit_code << " and error: " << error;
     return false;
+  } else if (!error.empty()) {
+    LOG(INFO) << "vpd_get_value succeeded but with following errors: " << error;
   }
 
   base::TrimWhitespaceASCII(value, base::TRIM_ALL, &value);
@@ -198,13 +200,14 @@
 }
 
 string HardwareChromeOS::GetECVersion() const {
-  string input_line;
+  string input_line, error;
   int exit_code = 0;
   vector<string> cmd = {"/usr/sbin/mosys", "-k", "ec", "info"};
 
-  bool success = Subprocess::SynchronousExec(cmd, &exit_code, &input_line);
-  if (!success || exit_code) {
-    LOG(ERROR) << "Unable to read ec info from mosys (" << exit_code << ")";
+  if (!Subprocess::SynchronousExec(cmd, &exit_code, &input_line, &error) ||
+      exit_code != 0) {
+    LOG(ERROR) << "Unable to read EC info from mosys with exit code: "
+               << exit_code << " and error: " << error;
     return "";
   }
 
@@ -353,22 +356,28 @@
 
 bool HardwareChromeOS::SetFirstActiveOmahaPingSent() {
   int exit_code = 0;
-  string output;
+  string output, error;
   vector<string> vpd_set_cmd = {
       "vpd", "-i", "RW_VPD", "-s", string(kActivePingKey) + "=1"};
-  if (!Subprocess::SynchronousExec(vpd_set_cmd, &exit_code, &output) ||
+  if (!Subprocess::SynchronousExec(vpd_set_cmd, &exit_code, &output, &error) ||
       exit_code) {
     LOG(ERROR) << "Failed to set vpd key for " << kActivePingKey
-               << " with exit code: " << exit_code << " with error: " << output;
+               << " with exit code: " << exit_code << " with output: " << output
+               << " and error: " << error;
     return false;
+  } else if (!error.empty()) {
+    LOG(INFO) << "vpd succeeded but with error logs: " << error;
   }
 
   vector<string> vpd_dump_cmd = {"dump_vpd_log", "--force"};
-  if (!Subprocess::SynchronousExec(vpd_dump_cmd, &exit_code, &output) ||
+  if (!Subprocess::SynchronousExec(vpd_dump_cmd, &exit_code, &output, &error) ||
       exit_code) {
     LOG(ERROR) << "Failed to cache " << kActivePingKey << " using dump_vpd_log"
-               << " with exit code: " << exit_code << " with error: " << output;
+               << " with exit code: " << exit_code << " with output: " << output
+               << " and error: " << error;
     return false;
+  } else if (!error.empty()) {
+    LOG(INFO) << "dump_vpd_log succeeded but with error logs: " << error;
   }
   return true;
 }
diff --git a/p2p_manager.cc b/p2p_manager.cc
index 6720908..5de91d1 100644
--- a/p2p_manager.cc
+++ b/p2p_manager.cc
@@ -249,12 +249,12 @@
 
 bool P2PManagerImpl::EnsureP2P(bool should_be_running) {
   int return_code = 0;
-  string output;
+  string stderr;
 
   may_be_running_ = true;  // Unless successful, we must be conservative.
 
   vector<string> args = configuration_->GetInitctlArgs(should_be_running);
-  if (!Subprocess::SynchronousExec(args, &return_code, &output)) {
+  if (!Subprocess::SynchronousExec(args, &return_code, nullptr, &stderr)) {
     LOG(ERROR) << "Error spawning " << utils::StringVectorToString(args);
     return false;
   }
@@ -268,7 +268,7 @@
     const char* expected_error_message =
         should_be_running ? "initctl: Job is already running: p2p\n"
                           : "initctl: Unknown instance \n";
-    if (output != expected_error_message)
+    if (stderr != expected_error_message)
       return false;
   }
 
diff --git a/payload_generator/squashfs_filesystem.cc b/payload_generator/squashfs_filesystem.cc
index e43bc0a..9838794 100644
--- a/payload_generator/squashfs_filesystem.cc
+++ b/payload_generator/squashfs_filesystem.cc
@@ -81,12 +81,12 @@
   // Run unsquashfs to get the system file map.
   // unsquashfs -m <map-file> <squashfs-file>
   vector<string> cmd = {"unsquashfs", "-m", map_file, sqfs_path};
-  string stdout;
+  string stdout, stderr;
   int exit_code;
-  if (!Subprocess::SynchronousExec(cmd, &exit_code, &stdout) ||
+  if (!Subprocess::SynchronousExec(cmd, &exit_code, &stdout, &stderr) ||
       exit_code != 0) {
-    LOG(ERROR) << "Failed to run unsquashfs -m. The stdout content was: "
-               << stdout;
+    LOG(ERROR) << "Failed to run `unsquashfs -m` with stdout content: "
+               << stdout << " and stderr content: " << stderr;
     return false;
   }
   TEST_AND_RETURN_FALSE(utils::ReadFile(map_file, map));
@@ -109,10 +109,12 @@
                         unsquash_dir.GetPath().value(),
                         sqfs_path,
                         kUpdateEngineConf};
+  string stdout, stderr;
   int exit_code;
-  if (!Subprocess::SynchronousExec(cmd, &exit_code, nullptr) ||
+  if (!Subprocess::SynchronousExec(cmd, &exit_code, &stdout, &stderr) ||
       exit_code != 0) {
-    PLOG(ERROR) << "Failed to unsquashfs etc/update_engine.conf: ";
+    PLOG(ERROR) << "Failed to unsquashfs etc/update_engine.conf with stdout: "
+                << stdout << " and stderr: " << stderr;
     return false;
   }
 
diff --git a/update_attempter.cc b/update_attempter.cc
index 18e5088..f5e2037 100644
--- a/update_attempter.cc
+++ b/update_attempter.cc
@@ -956,13 +956,9 @@
 }
 
 bool UpdateAttempter::RebootDirectly() {
-  vector<string> command;
-  command.push_back("/sbin/shutdown");
-  command.push_back("-r");
-  command.push_back("now");
-  LOG(INFO) << "Running \"" << base::JoinString(command, " ") << "\"";
+  vector<string> command = {"/sbin/shutdown", "-r", "now"};
   int rc = 0;
-  Subprocess::SynchronousExec(command, &rc, nullptr);
+  Subprocess::SynchronousExec(command, &rc, nullptr, nullptr);
   return rc == 0;
 }