diff --git a/scripts/postinstall.sh b/scripts/postinstall.sh
index bb75d776..471afd51 100755
--- a/scripts/postinstall.sh
+++ b/scripts/postinstall.sh
@@ -1,8 +1,65 @@
 #/bin/bash
 
-flow-typed install -s --overwrite
-rm flow-typed/npm/{react-i18next_v7.x.x.js,styled-components_v3.x.x.js,redux_*}
+function MAIN {
+  REBUILD_ELECTRON_NATIVE_DEPS
+  INSTALL_FLOW_TYPED
+}
 
-if [ "$SKIP_REBUILD" != "1" ]; then
-  electron-builder install-app-deps
-fi
+function GET_HASH_PATH {
+  HASH_NAME=$1
+  echo "./node_modules/.cache/LEDGER_HASH_$HASH_NAME"
+}
+
+function GET_HASH {
+  HASH_NAME=$1
+  HASH_PATH=`GET_HASH_PATH $HASH_NAME`
+  if [ ! -e "$HASH_PATH" ]; then
+    echo ''
+  else
+    HASH_CONTENT=`cat "$HASH_PATH"`
+    echo $HASH_CONTENT
+  fi
+}
+
+function SET_HASH {
+  HASH_NAME=$1
+  HASH_CONTENT=$2
+  echo "setting hash $HASH_NAME to $HASH_CONTENT"
+  HASH_PATH=`GET_HASH_PATH $HASH_NAME`
+  mkdir -p ./node_modules/.cache
+  echo $HASH_CONTENT > $HASH_PATH
+}
+
+function INSTALL_FLOW_TYPED {
+  LATEST_FLOW_TYPED_COMMIT_HASH=`curl --silent --header "Accept: application/vnd.github.VERSION.sha" https://api.github.com/repos/flowtype/flow-typed/commits/master`
+  CURRENT_FLOW_TYPED_HASH=`GET_HASH 'flow-typed'`
+  if [ "$LATEST_FLOW_TYPED_COMMIT_HASH" == "$CURRENT_FLOW_TYPED_HASH" ]; then
+    echo "> Flow-typed definitions are up to date. Skipping"
+  else
+    echo "> Installing flow-typed defs"
+    flow-typed install -s --overwrite
+    echo "> Removing broken flow definitions"
+    rm flow-typed/npm/{react-i18next_v7.x.x.js,styled-components_v3.x.x.js,redux_*}
+    SET_HASH 'flow-typed' $LATEST_FLOW_TYPED_COMMIT_HASH
+  fi
+}
+
+function REBUILD_ELECTRON_NATIVE_DEPS {
+  # for strange/fancy os-es
+  if [[ `uname` == 'Darwin' ]]; then
+    PACKAGE_JSON_HASH=`md5 package.json | cut -d ' ' -f 1`
+  else
+    # for normal os-es
+    PACKAGE_JSON_HASH=`md5sum package.json | cut -d ' ' -f 1`
+  fi
+  CACHED_PACKAGE_JSON_HASH=`GET_HASH 'package.json'`
+  if [ "$CACHED_PACKAGE_JSON_HASH" == "$PACKAGE_JSON_HASH" ]; then
+    echo "> Electron native deps are up to date. Skipping"
+  else
+    echo "> Installing electron native deps"
+    electron-builder install-app-deps
+    SET_HASH 'package.json' $PACKAGE_JSON_HASH
+  fi
+}
+
+MAIN