diff --git a/projects/opus/build.sh b/projects/opus/build.sh
index 4cdceb9e9d02..d80f3992983a 100644
--- a/projects/opus/build.sh
+++ b/projects/opus/build.sh
@@ -20,6 +20,7 @@ FUZZERS="opus_encode_fuzzer opus_multistream_decode_fuzzer opus_multistream_enco
 BUILDS=(floating fixed floating_qext fixed_qext)
 
 tar xvf $SRC/opus_testvectors.tar.gz
+zip -r $SRC/zipped-corpus.zip opus_testvectors/
 
 if [[ $CFLAGS = *sanitize=memory* ]]; then
   CFLAGS+=" -D_FORTIFY_SOURCE=0"
@@ -64,6 +65,8 @@ for build in "${BUILDS[@]}"; do
     # fuzzer's name
     [ -f tests/$fuzzer.options ] \
         && cp tests/$fuzzer.options $OUT/${fuzzer}_${build}.options
-    zip -r $OUT/${fuzzer}_${build}_seed_corpus.zip opus_testvectors/
+    cp $SRC/zipped-corpus.zip $OUT/${fuzzer}_${build}_seed_corpus.zip &
   done
 done
+
+wait