diff --git a/tests/test_tpm2_ibmtss2 b/tests/test_tpm2_ibmtss2
index b1c61250c..41118279c 100755
--- a/tests/test_tpm2_ibmtss2
+++ b/tests/test_tpm2_ibmtss2
@@ -104,7 +104,7 @@ if ! ./startup; then
 	exit 1
 fi
 
-./reg.sh -a 2>&1 | tee "${REGLOG}"
+OPENSSL_ENABLE_SHA1_SIGNATURES=1 ./reg.sh -a 2>&1 | tee "${REGLOG}"
 
 ret=0