diff --git a/enter_chroot.sh b/enter_chroot.sh
index 77b4722897..236aa02c09 100755
--- a/enter_chroot.sh
+++ b/enter_chroot.sh
@@ -24,6 +24,8 @@ DEFINE_string build_number "" \
   "The build-bot build number (when called by buildbot only)." "b"
 DEFINE_string chrome_root "" \
   "The root of your chrome browser source. Should contain a 'src' subdir."
+DEFINE_string automount_dir "/media" \
+  "The directory in which your host OS creates mountpoints for external media."
 
 DEFINE_boolean official_build $FLAGS_FALSE \
   "Set CHROMEOS_OFFICIAL=1 for release builds."
@@ -100,6 +102,13 @@ function setup_env {
           die "Could not mount $MOUNTED_PATH"
     fi
 
+    MOUNTED_PATH="$(readlink -f "${FLAGS_chroot}${FLAGS_automount_dir}")"
+    if [ -z "$(mount | grep -F "on $MOUNTED_PATH ")" ]
+    then
+      sudo mount --bind "${FLAGS_automount_dir}" "$MOUNTED_PATH" || \
+          die "Could not mount $MOUNTED_PATH"
+    fi
+
     MOUNTED_PATH="$(readlink -f "${FLAGS_chroot}$CHROOT_TRUNK_DIR")"
     if [ -z "$(mount | grep -F "on $MOUNTED_PATH ")" ]
     then
diff --git a/image_to_usb.sh b/image_to_usb.sh
index ff1a1bbd80..d1ac0b28a2 100755
--- a/image_to_usb.sh
+++ b/image_to_usb.sh
@@ -232,7 +232,14 @@ then
   echo "Attempting to unmount any mounts on the USB device..."
   for i in $(mount | grep ^"${FLAGS_to}" | awk '{print $1}')
   do
-    sudo umount "$i"
+    if sudo umount "$i" 2>&1 >/dev/null | grep "not found"; then
+      echo
+      echo "The device you have specified is already mounted at some point "
+      echo "that is not visible from inside the chroot.  Please unmount the "
+      echo "device manually from outside the chroot and try again."
+      echo
+      exit 1
+    fi
   done
   sleep 3