diff --git a/include/mcl/fp_tower.hpp b/include/mcl/fp_tower.hpp
index 95722e2..8d79a7e 100644
--- a/include/mcl/fp_tower.hpp
+++ b/include/mcl/fp_tower.hpp
@@ -283,9 +283,13 @@ public:
 	template<class InputStream>
 	void load(bool *pb, InputStream& is, int ioMode)
 	{
-		a.load(pb, is, ioMode);
+		Fp *ap = &a, *bp = &b;
+		if (Fp::isETHserialization_ && ioMode & (IoSerialize | IoSerializeHexStr)) {
+			fp::swap_(ap, bp);
+		}
+		ap->load(pb, is, ioMode);
 		if (!*pb) return;
-		b.load(pb, is, ioMode);
+		bp->load(pb, is, ioMode);
 	}
 	/*
 		Fp2T = <a> + ' ' + <b>
@@ -293,14 +297,18 @@ public:
 	template<class OutputStream>
 	void save(bool *pb, OutputStream& os, int ioMode) const
 	{
+		const Fp *ap = &a, *bp = &b;
+		if (Fp::isETHserialization_ && ioMode & (IoSerialize | IoSerializeHexStr)) {
+			fp::swap_(ap, bp);
+		}
 		const char sep = *fp::getIoSeparator(ioMode);
-		a.save(pb, os, ioMode);
+		ap->save(pb, os, ioMode);
 		if (!*pb) return;
 		if (sep) {
 			cybozu::writeChar(pb, os, sep);
 			if (!*pb) return;
 		}
-		b.save(pb, os, ioMode);
+		bp->save(pb, os, ioMode);
 	}
 	bool isZero() const { return a.isZero() && b.isZero(); }
 	bool isOne() const { return a.isOne() && b.isZero(); }
diff --git a/test/fp_tower_test.cpp b/test/fp_tower_test.cpp
index a7123f7..c26c5d7 100644
--- a/test/fp_tower_test.cpp
+++ b/test/fp_tower_test.cpp
@@ -146,6 +146,18 @@ void testFp2()
 		CYBOZU_TEST_ASSERT(Fp2::squareRoot(z, y));
 		CYBOZU_TEST_EQUAL(z * z, y);
 	}
+
+	// serialize
+	for (int i = 0; i < 2; i++) {
+		Fp::setETHserialization(i == 0);
+		Fp2 x, y;
+		x.setStr("0x1234567789345 0x23424324");
+		char buf[256];
+		size_t n = x.serialize(buf, sizeof(buf));
+		CYBOZU_TEST_ASSERT(n > 0);
+		CYBOZU_TEST_EQUAL(y.deserialize(buf, n), n);
+		CYBOZU_TEST_EQUAL(x, y);
+	}
 }
 
 void testFp6sqr(const Fp2& a, const Fp2& b, const Fp2& c, const Fp6& x)
@@ -390,6 +402,7 @@ void test(const char *p, mcl::fp::Mode mode)
 	Fp::init(xi_a, p, mode);
 	printf("mode=%s\n", mcl::fp::ModeToStr(mode));
 	Fp2::init();
+	printf("bitSize=%d\n", (int)Fp::getBitSize());
 #if 0
 	if (Fp::getBitSize() > 256) {
 		printf("not support p=%s\n", p);
@@ -446,7 +459,7 @@ void testAll()
 	};
 	for (size_t i = 0; i < CYBOZU_NUM_OF_ARRAY(tbl); i++) {
 		const char *p = tbl[i];
-		printf("prime=%s %d\n", p, (int)(strlen(p) - 2) * 4);
+		printf("prime=%s\n", p);
 		test(p, mcl::fp::FP_GMP);
 #ifdef MCL_USE_LLVM
 		test(p, mcl::fp::FP_LLVM);