diff --git a/library/ecp.c b/library/ecp.c
index 6675c47..a8c367a 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -1804,7 +1804,8 @@
     MBEDTLS_MPI_CHK( ecp_normalize_jac( grp, RR ) );
 
 #if defined(MBEDTLS_ECP_RESTARTABLE)
-    MBEDTLS_MPI_CHK( mbedtls_ecp_copy( R, RR ) );
+    if( rs_ctx != NULL && rs_ctx->rsm != NULL )
+        MBEDTLS_MPI_CHK( mbedtls_ecp_copy( R, RR ) );
 #endif
 
 cleanup: