diff --git a/tests/Makefile b/tests/Makefile
index faa7d019..853f4ee8 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -76,13 +76,13 @@ allnothread: fullbench fuzzer paramgrill datagen decodecorpus
 dll: fuzzer-dll zstreamtest-dll
 
 zstd:
-	$(MAKE) -C $(PRGDIR) $@ MOREFLAGS="$(DEBUGFLAGS)"
+	$(MAKE) -C $(PRGDIR) $@ MOREFLAGS+="$(DEBUGFLAGS)"
 
 zstd32:
-	$(MAKE) -C $(PRGDIR) $@ MOREFLAGS="$(DEBUGFLAGS)"
+	$(MAKE) -C $(PRGDIR) $@ MOREFLAGS+="$(DEBUGFLAGS)"
 
 zstd-nolegacy:
-	$(MAKE) -C $(PRGDIR) $@ MOREFLAGS="$(DEBUGFLAGS)"
+	$(MAKE) -C $(PRGDIR) $@ MOREFLAGS+="$(DEBUGFLAGS)"
 
 gzstd:
 	$(MAKE) -C $(PRGDIR) zstd HAVE_ZLIB=1 MOREFLAGS="$(DEBUGFLAGS)"
diff --git a/tests/playTests.sh b/tests/playTests.sh
index 6b78b305..67732d3a 100755
--- a/tests/playTests.sh
+++ b/tests/playTests.sh
@@ -297,8 +297,11 @@ cp $TESTFILE tmp
 $ZSTD -f tmp -D tmpDict
 $ZSTD -d tmp.zst -D tmpDict -fo result
 $DIFF $TESTFILE result
-$ECHO "- Test dictionary compression with multithreading "
-./datagen -g5M | $ZSTD -T2 -D tmpDict | $ZSTD -t -D tmpDict   # fails with v1.3.2 
+if [ -n "$hasMT" ]
+then
+    $ECHO "- Test dictionary compression with multithreading "
+    ./datagen -g5M | $ZSTD -T2 -D tmpDict | $ZSTD -t -D tmpDict   # fails with v1.3.2 
+fi
 $ECHO "- Create second (different) dictionary "
 $ZSTD --train *.c ../programs/*.c ../programs/*.h -o tmpDictC
 $ZSTD -d tmp.zst -D tmpDictC -fo result && die "wrong dictionary not detected!"