diff --git a/build b/build
index f56f34c..d155e58 100755
--- a/build
+++ b/build
@@ -3,31 +3,45 @@ DATA_SUBDIR=data
 
 set -e
 
-if git submodule status $DATA_SUBDIR | grep -q '^-'; then
-  echo "$DATA_SUBDIR/ is not an initialized submodule"; exit 1
-fi
-if ! [ -e $DATA_SUBDIR/.git/annex ]; then
-  echo "$DATA_SUBDIR/ is not a git annex repository"; exit 1
-fi
-if ! (cd $DATA_SUBDIR && git annex version | grep -q 'local repository version: 7'); then
-  echo "$DATA_SUBDIR/ is not a git annex repository version 7"; exit 1
-fi
-if ! (cd $DATA_SUBDIR && git remote | grep -q '^nfs$'); then
-  echo "$DATA_SUBDIR/ has no git remote 'nfs'"; exit 1
-fi
+check_data_subdir() {
+  result=0
 
-# XXX
-#git submodule update --init
-#(cd data && git annex init --version=7)
-#(cd data && git remote add nfs /path/to/GitNX-Repository/qurator/qurator-data)
+  if git submodule status $DATA_SUBDIR | grep -q '^-'; then
+    echo "$DATA_SUBDIR/ is not an initialized submodule"; result=1
+  fi
+  if ! [ -e $DATA_SUBDIR/.git/annex ]; then
+    echo "$DATA_SUBDIR/ is not a git annex repository"; result=1
+  fi
+  if ! (cd $DATA_SUBDIR && git annex version | grep -q 'local repository version: 7'); then
+    echo "$DATA_SUBDIR/ is not a git annex repository version 7"; result=1
+  fi
+  if ! (cd $DATA_SUBDIR && git remote | grep -q '^nfs$'); then
+    echo "$DATA_SUBDIR/ has no git remote 'nfs'"; result=1
+  fi
 
+  return $result
+}
 
-(
-  cd data
-  for f in "calamari-models/GT4HistOCR/*.ckpt*" "tesseract-models/GT4HistOCR/*.traineddata" "textline_detection/*.h5"; do
-    git annex get $f
-    git annex fsck $f
+download=0
+if ! check_data_subdir; then
+  select choice in "Abort to $DATA_SUBDIR" "Download data files"; do
+    if [ $REPLY = 1 ]; then
+      #git submodule update --init
+      #(cd data && git annex init --version=7)
+      #(cd data && git remote add nfs /path/to/GitNX-Repository/qurator/qurator-data)
+      exit
+    else
+      download=1
+    fi
   done
-)
+else
+  (
+    cd data
+    for f in "calamari-models/GT4HistOCR/*.ckpt*" "tesseract-models/GT4HistOCR/*.traineddata" "textline_detection/*.h5"; do
+      git annex get $f
+      git annex fsck $f
+    done
+  )
+fi
 
 docker build -t my_ocrd_workflow .