diff --git a/src/cmd/asm/internal/asm/testdata/s390x.s b/src/cmd/asm/internal/asm/testdata/s390x.s
index 03b84cfa62..7c5d26be33 100644
--- a/src/cmd/asm/internal/asm/testdata/s390x.s
+++ b/src/cmd/asm/internal/asm/testdata/s390x.s
@@ -412,6 +412,8 @@ TEXT main·foo(SB),DUPOK|NOSPLIT,$16-0 // TEXT main.foo(SB), DUPOK|NOSPLIT, $16-
 	UNDEF                          // 00000000
 	NOPH                           // 0700
 
+	SYNC                           // 07e0
+
 	// vector add and sub instructions
 	VAB	V3, V4, V4              // e743400000f3
 	VAH	V3, V4, V4              // e743400010f3
diff --git a/src/cmd/internal/obj/s390x/asmz.go b/src/cmd/internal/obj/s390x/asmz.go
index f0f9d5cefc..06921085c9 100644
--- a/src/cmd/internal/obj/s390x/asmz.go
+++ b/src/cmd/internal/obj/s390x/asmz.go
@@ -3700,7 +3700,7 @@ func (c *ctxtz) asmout(p *obj.Prog, asm *[]byte) {
 		}
 
 	case 80: // sync
-		zRR(op_BCR, uint32(NotEqual), 0, asm)
+		zRR(op_BCR, 14, 0, asm) // fast-BCR-serialization
 
 	case 81: // float to fixed and fixed to float moves (no conversion)
 		switch p.As {