diff --git a/build.sh b/build.sh
index 2cae71b..1031d76 100755
--- a/build.sh
+++ b/build.sh
@@ -24,8 +24,6 @@ export QUILT_REFRESH_ARGS='-p ab'
 source "$FUNCTIONS_DIR/logging.sh"
 source "$FUNCTIONS_DIR/dependencies_check.sh"
 
-source "$SCRIPT_DIR/common.sh"
-
 on_chroot() {
   local proc_fs="$ROOTFS_DIR/proc"
   local dev_fs="$ROOTFS_DIR/dev"
@@ -75,6 +73,40 @@ apply_patches() {
   popd > /dev/null
 }
 
+unmount() {
+  if [ -z "$1" ]; then
+    DIR=$PWD
+  else
+    DIR=$1
+  fi
+
+  while mount | grep -q "$DIR"; do
+    local LOCS
+    LOCS=$(mount | grep "$DIR" | cut -f 3 -d ' ' | sort -r)
+    for loc in $LOCS; do
+      umount "$loc"
+    done
+  done
+}
+
+unmount_image() {
+  sync
+  sleep 1
+  local LOOP_DEVICES
+  LOOP_DEVICES=$(losetup -j "${1}" | cut -f1 -d':')
+  for LOOP_DEV in ${LOOP_DEVICES}; do
+    if [ -n "${LOOP_DEV}" ]; then
+      local MOUNTED_DIR
+      MOUNTED_DIR=$(mount | grep "$(basename "${LOOP_DEV}")" | head -n 1 | cut -f 3 -d ' ')
+      if [ -n "${MOUNTED_DIR}" ] && [ "${MOUNTED_DIR}" != "/" ]; then
+        unmount "$(dirname "${MOUNTED_DIR}")"
+      fi
+      sleep 1
+      losetup -d "${LOOP_DEV}"
+    fi
+  done
+}
+
 if [ "$(id -u)" != '0' ]; then
   echo 'Please run as root' 1>&2
   exit 1
diff --git a/scripts/common.sh b/scripts/common.sh
deleted file mode 100644
index 7a2c2d4..0000000
--- a/scripts/common.sh
+++ /dev/null
@@ -1,36 +0,0 @@
-unmount() {
-  if [ -z "$1" ]; then
-    DIR=$PWD
-  else
-    DIR=$1
-  fi
-
-  while mount | grep -q "$DIR"; do
-    local LOCS
-    LOCS=$(mount | grep "$DIR" | cut -f 3 -d ' ' | sort -r)
-    for loc in $LOCS; do
-      umount "$loc"
-    done
-  done
-}
-
-unmount_image() {
-  sync
-  sleep 1
-  local LOOP_DEVICES
-  LOOP_DEVICES=$(losetup -j "${1}" | cut -f1 -d':')
-  for LOOP_DEV in ${LOOP_DEVICES}; do
-    if [ -n "${LOOP_DEV}" ]; then
-      local MOUNTED_DIR
-      MOUNTED_DIR=$(mount | grep "$(basename "${LOOP_DEV}")" | head -n 1 | cut -f 3 -d ' ')
-      if [ -n "${MOUNTED_DIR}" ] && [ "${MOUNTED_DIR}" != "/" ]; then
-        unmount "$(dirname "${MOUNTED_DIR}")"
-      fi
-      sleep 1
-      losetup -d "${LOOP_DEV}"
-    fi
-  done
-}
-
-export -f unmount
-export -f unmount_image