diff --git a/library/ecp.c b/library/ecp.c
index 6087256..f5d43d5 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -43,9 +43,7 @@
 
 #include "common.h"
 
-#include "ecp_invasive.h"
-
-#if defined(MBEDTLS_ECP_WITH_MPI_STRUCT)
+#if !defined(MBEDTLS_ECP_WITH_MPI_UINT)
 
 /**
  * \brief Function level alternative implementation.
@@ -84,6 +82,7 @@
 #include "mbedtls/error.h"
 
 #include "bn_mul.h"
+#include "ecp_invasive.h"
 
 #include <string.h>
 
@@ -3653,4 +3652,4 @@
 
 #endif /* MBEDTLS_ECP_LIGHT */
 
-#endif /* MBEDTLS_ECP_WITH_MPI_STRUCT */
+#endif /* MBEDTLS_ECP_WITH_MPI_UINT */
diff --git a/library/ecp_invasive.h b/library/ecp_invasive.h
index 456ac21..c4a0a4d 100644
--- a/library/ecp_invasive.h
+++ b/library/ecp_invasive.h
@@ -40,23 +40,13 @@
     MBEDTLS_ECP_MOD_SCALAR
 } mbedtls_ecp_modulus_type;
 
-/* Requred macros for ECP split.
- * If MBEDTLS_ECP_WITH_MPI_UINT is defined the new bignum interface is used.
- */
-#if !defined(MBEDTLS_ECP_WITH_MPI_UINT)
-
 /* Provide a commented-out definition so that `check_names.py` knows that
  * it's not a typo.
  * MBEDTLS_ECP_WITH_MPI_UINT must not be defined within config files, but
- * only on the command line, as otherwise both ECP implementations will be
- * built.
+ * only on the command line.
  */
 //#define MBEDTLS_ECP_WITH_MPI_UINT
 
-/* Enable the old bignum interface. */
-#define MBEDTLS_ECP_WITH_MPI_STRUCT
-#endif
-
 typedef enum {
     MBEDTLS_ECP_VARIANT_NONE            = 0,
     MBEDTLS_ECP_VARIANT_WITH_MPI_STRUCT = 1,
diff --git a/library/ecp_new.c b/library/ecp_new.c
index 3df6f9f..028a33b 100644
--- a/library/ecp_new.c
+++ b/library/ecp_new.c
@@ -43,8 +43,6 @@
 
 #include "common.h"
 
-#include "ecp_invasive.h"
-
 #if defined(MBEDTLS_ECP_WITH_MPI_UINT)
 
 /**
@@ -84,6 +82,7 @@
 #include "mbedtls/error.h"
 
 #include "bn_mul.h"
+#include "ecp_invasive.h"
 
 #include <string.h>