diff --git a/Makefile b/Makefile
index a98772faea6dca..eeb65c38e05eb6 100644
--- a/Makefile
+++ b/Makefile
@@ -203,7 +203,7 @@ coverage: coverage-test ## Run the tests and generate a coverage report.
 coverage-build: all
 	mkdir -p node_modules
 	if [ ! -d node_modules/nyc ]; then \
-		$(NODE) ./deps/npm install nyc --no-save --no-package-lock; fi
+		$(NODE) ./deps/npm install nyc@13 --no-save --no-package-lock; fi
 	if [ ! -d gcovr ]; then git clone -b 3.4 --depth=1 \
 		--single-branch git://github.com/gcovr/gcovr.git; fi
 	if [ ! -d build ]; then git clone --depth=1 \
@@ -234,8 +234,9 @@ coverage-test: coverage-build
 	$(NODE) ./node_modules/.bin/nyc merge 'out/Release/.coverage' \
 		.cov_tmp/libcov.json
 	(cd lib && .$(NODE) ../node_modules/.bin/nyc report \
-		--temp-directory "$(CURDIR)/.cov_tmp" \
-		--report-dir "$(CURDIR)/coverage")
+		--temp-dir "$(CURDIR)/.cov_tmp" \
+		--report-dir "$(CURDIR)/coverage" \
+		--reporter html)
 	-(cd out && "../gcovr/scripts/gcovr" --gcov-exclude='.*deps' \
 		--gcov-exclude='.*usr' -v -r Release/obj.target \
 		--html --html-detail -o ../coverage/cxxcoverage.html \