diff --git a/include/mcl/bn.hpp b/include/mcl/bn.hpp
index 5ebe5d9..eb22c6b 100644
--- a/include/mcl/bn.hpp
+++ b/include/mcl/bn.hpp
@@ -1100,11 +1100,11 @@ struct Param {
 		} else {
 			twist_b_type = tb_generic;
 		}
-		G1::init(0, cp.b, mcl::ec::Proj);
+		G1::init(0, cp.b, mcl::ec::Jacobi);
 		if (isBLS12) {
 			G1::setOrder(r);
 		}
-		G2::init(0, twist_b, mcl::ec::Proj);
+		G2::init(0, twist_b, mcl::ec::Jacobi);
 		G2::setOrder(r);
 
 		const mpz_class largest_c = isBLS12 ? abs_z : gmp::abs(z * 6 + 2);