diff --git a/os/emscripten/deploy-webapp.sh b/os/emscripten/deploy-webapp.sh
index bd970dd3c1..877ea08f12 100755
--- a/os/emscripten/deploy-webapp.sh
+++ b/os/emscripten/deploy-webapp.sh
@@ -2,6 +2,8 @@
 
 INSTALL_PATH=`pwd`/../../../openttd-touch-webapp
 
+export NO_CLEAN=1
+
 ./emscripten-build.sh release $INSTALL_PATH || exit 1
 
 cd $INSTALL_PATH || exit 1
diff --git a/os/emscripten/emscripten-build.sh b/os/emscripten/emscripten-build.sh
index 9b779c42f5..e1a6805bbb 100755
--- a/os/emscripten/emscripten-build.sh
+++ b/os/emscripten/emscripten-build.sh
@@ -90,7 +90,7 @@ mkdir -p baseset
 									-DTimidity_INCLUDE_DIR=`pwd`/libtimidity-0.2.7/build-wasm/include \
 									 || exit 1
 
-rm -f openttd.html
+[ -z "$NO_CLEAN" ] && rm -f openttd.html
 emmake make -j8 VERBOSE=1 || exit 1
 
 cp -f *.html *.js *.data *.wasm ../media/openttd.256.png ../os/emscripten/openttd.webapp "$INSTALL_PATH"