diff --git a/ChangeLog b/ChangeLog
index e5b6a24b7..43dfb9977 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -49,6 +49,8 @@ Bugfix
    * Add explicit integer to enumeration type casts to example program
      programs/pkey/gen_key which previously led to compilation failure
      on some toolchains. Reported by phoenixmcallister. Fixes #2170.
+   * Fix double initialization of ECC hardware that made some accelerators
+     hang.
 
 = mbed TLS 2.14.0 branch released 2018-11-19
 
diff --git a/include/mbedtls/check_config.h b/include/mbedtls/check_config.h
index b0f11a982..b86e5807e 100644
--- a/include/mbedtls/check_config.h
+++ b/include/mbedtls/check_config.h
@@ -114,6 +114,7 @@
       defined(MBEDTLS_ECDSA_SIGN_ALT)          || \
       defined(MBEDTLS_ECDSA_VERIFY_ALT)        || \
       defined(MBEDTLS_ECDSA_GENKEY_ALT)        || \
+      defined(MBEDTLS_ECP_INTERNAL_ALT)        || \
       defined(MBEDTLS_ECP_ALT) )
 #error "MBEDTLS_ECP_RESTARTABLE defined, but it cannot coexist with an alternative ECP implementation"
 #endif
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 16ed503ca..87a81c9ea 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -414,11 +414,11 @@
  *      unsigned char mbedtls_internal_ecp_grp_capable(
  *          const mbedtls_ecp_group *grp )
  *      int  mbedtls_internal_ecp_init( const mbedtls_ecp_group *grp )
- *      void mbedtls_internal_ecp_deinit( const mbedtls_ecp_group *grp )
+ *      void mbedtls_internal_ecp_free( const mbedtls_ecp_group *grp )
  * The mbedtls_internal_ecp_grp_capable function should return 1 if the
  * replacement functions implement arithmetic for the given group and 0
  * otherwise.
- * The functions mbedtls_internal_ecp_init and mbedtls_internal_ecp_deinit are
+ * The functions mbedtls_internal_ecp_init and mbedtls_internal_ecp_free are
  * called before and after each point operation and provide an opportunity to
  * implement optimized set up and tear down instructions.
  *
diff --git a/library/ecp.c b/library/ecp.c
index 4f7e5e440..7fefb4c16 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -47,6 +47,35 @@
 #include MBEDTLS_CONFIG_FILE
 #endif
 
+/**
+ * \brief Function level alternative implementation.
+ *
+ * The MBEDTLS_ECP_INTERNAL_ALT macro enables alternative implementations to
+ * replace certain functions in this module. The alternative implementations are
+ * typically hardware accelerators and need to activate the hardware before the
+ * computation starts and deactivate it after it finishes. The
+ * mbedtls_internal_ecp_init() and mbedtls_internal_ecp_free() functions serve
+ * this purpose.
+ *
+ * To preserve the correct functionality the following conditions must hold:
+ *
+ * - The alternative implementation must be activated by
+ *   mbedtls_internal_ecp_init() before any of the replaceable functions is
+ *   called.
+ * - mbedtls_internal_ecp_free() must \b only be called when the alternative
+ *   implementation is activated.
+ * - mbedtls_internal_ecp_init() must \b not be called when the alternative
+ *   implementation is activated.
+ * - Public functions must not return while the alternative implementation is
+ *   activated.
+ * - Replaceable functions are guarded by \c MBEDTLS_ECP_XXX_ALT macros and
+ *   before calling them an \code if( mbedtls_internal_ecp_grp_capable( grp ) )
+ *   \endcode ensures that the alternative implementation supports the current
+ *   group.
+ */
+#if defined(MBEDTLS_ECP_INTERNAL_ALT)
+#endif
+
 #if defined(MBEDTLS_ECP_C)
 
 #include "mbedtls/ecp.h"
@@ -2412,11 +2441,6 @@ int mbedtls_ecp_muladd_restartable(
 
     mbedtls_ecp_point_init( &mP );
 
-#if defined(MBEDTLS_ECP_INTERNAL_ALT)
-    if( ( is_grp_capable = mbedtls_internal_ecp_grp_capable( grp ) ) )
-        MBEDTLS_MPI_CHK( mbedtls_internal_ecp_init( grp ) );
-#endif /* MBEDTLS_ECP_INTERNAL_ALT */
-
     ECP_RS_ENTER( ma );
 
 #if defined(MBEDTLS_ECP_RESTARTABLE)
@@ -2444,6 +2468,12 @@ int mbedtls_ecp_muladd_restartable(
 mul2:
 #endif
     MBEDTLS_MPI_CHK( mbedtls_ecp_mul_shortcuts( grp, pR,  n, Q, rs_ctx ) );
+
+#if defined(MBEDTLS_ECP_INTERNAL_ALT)
+    if( ( is_grp_capable = mbedtls_internal_ecp_grp_capable( grp ) ) )
+        MBEDTLS_MPI_CHK( mbedtls_internal_ecp_init( grp ) );
+#endif /* MBEDTLS_ECP_INTERNAL_ALT */
+
 #if defined(MBEDTLS_ECP_RESTARTABLE)
     if( rs_ctx != NULL && rs_ctx->ma != NULL )
         rs_ctx->ma->state = ecp_rsma_add;