diff --git a/include/mbedtls/config_adjust_legacy_from_psa.h b/include/mbedtls/config_adjust_legacy_from_psa.h
index cc29d0bbd..777186e87 100644
--- a/include/mbedtls/config_adjust_legacy_from_psa.h
+++ b/include/mbedtls/config_adjust_legacy_from_psa.h
@@ -28,85 +28,210 @@
 #ifndef MBEDTLS_CONFIG_ADJUST_LEGACY_FROM_PSA_H
 #define MBEDTLS_CONFIG_ADJUST_LEGACY_FROM_PSA_H
 
+/*
+ * ECC: support for a feature is controlled by a triplet or a pair:
+ * (curve, key_type basic, alg) or (curve, key_type_<action>).
+ *
+ * A triplet is accelerated if all of is components are accelerated;
+ * otherwise each component needs to be built in.
+ *
+ * In addition, the set of features supported is the full cross-product:
+ * if (a, b) and (c, d) are supported, so are (a, d) and (c, b). At this
+ * point, the same holds for the set of accelerated features.
+ *
+ * So, we end up with as simple alternative:
+ * - either each curve, key type and alg that is requested is accelerated, and
+ *   we don't need any built-in implementation;
+ * - or at least one curve, key type or alg is requested but not accelerated,
+ *   and we enable built-ins for each curve, key type, and alg.
+ *
+ * This is implemented in two passes:
+ * 1. Check if everything is accelerated.
+ * 2. If not, enable built-ins for each item that was requested.
+ *
+ * Note: this needs psa/crypto_adjust_keypair_types.h to have been included
+ * already, so that we know the full set of key types that are requested.
+ */
+
+/* ECC: curves: is everything accelerated? */
+#if defined(PSA_WANT_ECC_BRAINPOOL_P_R1_256) && \
+    !defined(MBEDTLS_PSA_ACCEL_ECC_BRAINPOOL_P_R1_256)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_ECC_BRAINPOOL_P_R1_384) && \
+    !defined(MBEDTLS_PSA_ACCEL_ECC_BRAINPOOL_P_R1_384)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_ECC_BRAINPOOL_P_R1_512) && \
+    !defined(MBEDTLS_PSA_ACCEL_ECC_BRAINPOOL_P_R1_512)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_ECC_MONTGOMERY_255) && \
+    !defined(MBEDTLS_PSA_ACCEL_ECC_MONTGOMERY_255)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_ECC_MONTGOMERY_448) && \
+    !defined(MBEDTLS_PSA_ACCEL_ECC_MONTGOMERY_448)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_ECC_SECP_R1_192) && \
+    !defined(MBEDTLS_PSA_ACCEL_ECC_SECP_R1_192)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_ECC_SECP_R1_224) && \
+    !defined(MBEDTLS_PSA_ACCEL_ECC_SECP_R1_224)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_ECC_SECP_R1_256) && \
+    !defined(MBEDTLS_PSA_ACCEL_ECC_SECP_R1_256)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_ECC_SECP_R1_384) && \
+    !defined(MBEDTLS_PSA_ACCEL_ECC_SECP_R1_384)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_ECC_SECP_R1_521) && \
+    !defined(MBEDTLS_PSA_ACCEL_ECC_SECP_R1_521)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_ECC_SECP_K1_192) && \
+    !defined(MBEDTLS_PSA_ACCEL_ECC_SECP_K1_192)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_ECC_SECP_K1_224) && \
+    !defined(MBEDTLS_PSA_ACCEL_ECC_SECP_K1_224)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_ECC_SECP_K1_256) && \
+    !defined(MBEDTLS_PSA_ACCEL_ECC_SECP_K1_256)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+/* ECC: algs: is everything accelerated? */
+#if defined(PSA_WANT_ALG_DETERMINISTIC_ECDSA) && \
+    !defined(MBEDTLS_PSA_ACCEL_ALG_DETERMINISTIC_ECDSA)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_ALG_ECDH) && \
+    !defined(MBEDTLS_PSA_ACCEL_ALG_ECDH)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_ALG_ECDSA) && \
+    !defined(MBEDTLS_PSA_ACCEL_ALG_ECDSA)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_ALG_JPAKE) && \
+    !defined(MBEDTLS_PSA_ACCEL_ALG_JPAKE)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+/* ECC: key types: is everything accelerated? */
+#if defined(PSA_WANT_KEY_TYPE_ECC_PUBLIC_KEY) && \
+    !defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_PUBLIC_KEY)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_BASIC) && \
+    !defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR_BASIC)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_IMPORT) && \
+    !defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR_IMPORT)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_EXPORT) && \
+    !defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR_EXPORT)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_GENERATE) && \
+    !defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR_GENERATE)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+#if defined(PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_DERIVE) && \
+    !defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR_DERIVE)
+#define MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE
+#endif
+
+/* ECC: if acceleration is incomplete,
+ * enable built-ins for everything that's requested */
+#if defined(MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE)
+
+/* ECC: curves: enable built-ins */
 #if defined(PSA_WANT_ECC_BRAINPOOL_P_R1_256)
-#if !defined(MBEDTLS_PSA_ACCEL_ECC_BRAINPOOL_P_R1_256)
 #define MBEDTLS_ECP_DP_BP256R1_ENABLED
 #define MBEDTLS_PSA_BUILTIN_ECC_BRAINPOOL_P_R1_256 1
-#endif /* !MBEDTLS_PSA_ACCEL_ECC_BRAINPOOL_P_R1_256 */
 #endif /* PSA_WANT_ECC_BRAINPOOL_P_R1_256 */
 
 #if defined(PSA_WANT_ECC_BRAINPOOL_P_R1_384)
-#if !defined(MBEDTLS_PSA_ACCEL_ECC_BRAINPOOL_P_R1_384)
 #define MBEDTLS_ECP_DP_BP384R1_ENABLED
 #define MBEDTLS_PSA_BUILTIN_ECC_BRAINPOOL_P_R1_384 1
-#endif /* !MBEDTLS_PSA_ACCEL_ECC_BRAINPOOL_P_R1_384 */
 #endif /* PSA_WANT_ECC_BRAINPOOL_P_R1_384 */
 
 #if defined(PSA_WANT_ECC_BRAINPOOL_P_R1_512)
-#if !defined(MBEDTLS_PSA_ACCEL_ECC_BRAINPOOL_P_R1_512)
 #define MBEDTLS_ECP_DP_BP512R1_ENABLED
 #define MBEDTLS_PSA_BUILTIN_ECC_BRAINPOOL_P_R1_512 1
-#endif /* !MBEDTLS_PSA_ACCEL_ECC_BRAINPOOL_P_R1_512 */
 #endif /* PSA_WANT_ECC_BRAINPOOL_P_R1_512 */
 
 #if defined(PSA_WANT_ECC_MONTGOMERY_255)
-#if !defined(MBEDTLS_PSA_ACCEL_ECC_MONTGOMERY_255)
 #define MBEDTLS_ECP_DP_CURVE25519_ENABLED
 #define MBEDTLS_PSA_BUILTIN_ECC_MONTGOMERY_255 1
-#endif /* !MBEDTLS_PSA_ACCEL_ECC_MONTGOMERY_255 */
 #endif /* PSA_WANT_ECC_MONTGOMERY_255 */
 
 #if defined(PSA_WANT_ECC_MONTGOMERY_448)
-#if !defined(MBEDTLS_PSA_ACCEL_ECC_MONTGOMERY_448)
 #define MBEDTLS_ECP_DP_CURVE448_ENABLED
 #define MBEDTLS_PSA_BUILTIN_ECC_MONTGOMERY_448 1
-#endif /* !MBEDTLS_PSA_ACCEL_ECC_MONTGOMERY_448 */
 #endif /* PSA_WANT_ECC_MONTGOMERY_448 */
 
 #if defined(PSA_WANT_ECC_SECP_R1_192)
-#if !defined(MBEDTLS_PSA_ACCEL_ECC_SECP_R1_192)
 #define MBEDTLS_ECP_DP_SECP192R1_ENABLED
 #define MBEDTLS_PSA_BUILTIN_ECC_SECP_R1_192 1
-#endif /* !MBEDTLS_PSA_ACCEL_ECC_SECP_R1_192 */
 #endif /* PSA_WANT_ECC_SECP_R1_192 */
 
 #if defined(PSA_WANT_ECC_SECP_R1_224)
-#if !defined(MBEDTLS_PSA_ACCEL_ECC_SECP_R1_224)
 #define MBEDTLS_ECP_DP_SECP224R1_ENABLED
 #define MBEDTLS_PSA_BUILTIN_ECC_SECP_R1_224 1
-#endif /* !MBEDTLS_PSA_ACCEL_ECC_SECP_R1_224 */
 #endif /* PSA_WANT_ECC_SECP_R1_224 */
 
 #if defined(PSA_WANT_ECC_SECP_R1_256)
-#if !defined(MBEDTLS_PSA_ACCEL_ECC_SECP_R1_256)
 #define MBEDTLS_ECP_DP_SECP256R1_ENABLED
 #define MBEDTLS_PSA_BUILTIN_ECC_SECP_R1_256 1
-#endif /* !MBEDTLS_PSA_ACCEL_ECC_SECP_R1_256 */
 #endif /* PSA_WANT_ECC_SECP_R1_256 */
 
 #if defined(PSA_WANT_ECC_SECP_R1_384)
-#if !defined(MBEDTLS_PSA_ACCEL_ECC_SECP_R1_384)
 #define MBEDTLS_ECP_DP_SECP384R1_ENABLED
 #define MBEDTLS_PSA_BUILTIN_ECC_SECP_R1_384 1
-#endif /* !MBEDTLS_PSA_ACCEL_ECC_SECP_R1_384 */
 #endif /* PSA_WANT_ECC_SECP_R1_384 */
 
 #if defined(PSA_WANT_ECC_SECP_R1_521)
-#if !defined(MBEDTLS_PSA_ACCEL_ECC_SECP_R1_521)
 #define MBEDTLS_ECP_DP_SECP521R1_ENABLED
 #define MBEDTLS_PSA_BUILTIN_ECC_SECP_R1_521 1
-#endif /* !MBEDTLS_PSA_ACCEL_ECC_SECP_R1_521 */
 #endif /* PSA_WANT_ECC_SECP_R1_521 */
 
 #if defined(PSA_WANT_ECC_SECP_K1_192)
-#if !defined(MBEDTLS_PSA_ACCEL_ECC_SECP_K1_192)
 #define MBEDTLS_ECP_DP_SECP192K1_ENABLED
 #define MBEDTLS_PSA_BUILTIN_ECC_SECP_K1_192 1
-#endif /* !MBEDTLS_PSA_ACCEL_ECC_SECP_K1_192 */
 #endif /* PSA_WANT_ECC_SECP_K1_192 */
 
 #if defined(PSA_WANT_ECC_SECP_K1_224)
-#if !defined(MBEDTLS_PSA_ACCEL_ECC_SECP_K1_224)
 /*
  * SECP224K1 is buggy via the PSA API in Mbed TLS
  * (https://github.com/Mbed-TLS/mbedtls/issues/3541).
@@ -114,94 +239,85 @@
 #error "SECP224K1 is buggy via the PSA API in Mbed TLS."
 #define MBEDTLS_ECP_DP_SECP224K1_ENABLED
 #define MBEDTLS_PSA_BUILTIN_ECC_SECP_K1_224 1
-#endif /* !MBEDTLS_PSA_ACCEL_ECC_SECP_K1_224 */
 #endif /* PSA_WANT_ECC_SECP_K1_224 */
 
 #if defined(PSA_WANT_ECC_SECP_K1_256)
-#if !defined(MBEDTLS_PSA_ACCEL_ECC_SECP_K1_256)
 #define MBEDTLS_ECP_DP_SECP256K1_ENABLED
 #define MBEDTLS_PSA_BUILTIN_ECC_SECP_K1_256 1
-#endif /* !MBEDTLS_PSA_ACCEL_ECC_SECP_K1_256 */
 #endif /* PSA_WANT_ECC_SECP_K1_256 */
 
+/* ECC: algs: enable built-ins */
 #if defined(PSA_WANT_ALG_DETERMINISTIC_ECDSA)
-#if !defined(MBEDTLS_PSA_ACCEL_ALG_DETERMINISTIC_ECDSA) || defined(MBEDTLS_SOME_BUILTIN_EC)
 #define MBEDTLS_PSA_BUILTIN_ALG_DETERMINISTIC_ECDSA 1
 #define MBEDTLS_ECDSA_DETERMINISTIC
 #define MBEDTLS_ECDSA_C
 #define MBEDTLS_HMAC_DRBG_C
 #define MBEDTLS_MD_C
-#endif /* !MBEDTLS_PSA_ACCEL_ALG_DETERMINISTIC_ECDSA */
 #endif /* PSA_WANT_ALG_DETERMINISTIC_ECDSA */
 
 #if defined(PSA_WANT_ALG_ECDH)
-#if !defined(MBEDTLS_PSA_ACCEL_ALG_ECDH) || defined(MBEDTLS_SOME_BUILTIN_EC)
 #define MBEDTLS_PSA_BUILTIN_ALG_ECDH 1
 #define MBEDTLS_ECDH_C
 #define MBEDTLS_ECP_C
 #define MBEDTLS_BIGNUM_C
-#endif /* !MBEDTLS_PSA_ACCEL_ALG_ECDH */
 #endif /* PSA_WANT_ALG_ECDH */
 
 #if defined(PSA_WANT_ALG_ECDSA)
-#if !defined(MBEDTLS_PSA_ACCEL_ALG_ECDSA) || defined(MBEDTLS_SOME_BUILTIN_EC)
 #define MBEDTLS_PSA_BUILTIN_ALG_ECDSA 1
 #define MBEDTLS_ECDSA_C
 #define MBEDTLS_ECP_C
 #define MBEDTLS_BIGNUM_C
 #define MBEDTLS_ASN1_PARSE_C
 #define MBEDTLS_ASN1_WRITE_C
-#endif /* !MBEDTLS_PSA_ACCEL_ALG_ECDSA */
 #endif /* PSA_WANT_ALG_ECDSA */
 
 #if defined(PSA_WANT_ALG_JPAKE)
-#if !defined(MBEDTLS_PSA_ACCEL_ALG_JPAKE) || defined(MBEDTLS_SOME_BUILTIN_EC)
 #define MBEDTLS_PSA_BUILTIN_PAKE 1
 #define MBEDTLS_PSA_BUILTIN_ALG_JPAKE 1
 #define MBEDTLS_ECP_DP_SECP256R1_ENABLED
 #define MBEDTLS_BIGNUM_C
 #define MBEDTLS_ECP_C
 #define MBEDTLS_ECJPAKE_C
-#endif /* MBEDTLS_PSA_ACCEL_ALG_JPAKE */
 #endif /* PSA_WANT_ALG_JPAKE */
 
+/* ECC: key types: enable built-ins */
 #if defined(PSA_WANT_KEY_TYPE_ECC_PUBLIC_KEY)
-#if !defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_PUBLIC_KEY)
 #define MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_PUBLIC_KEY 1
 #define MBEDTLS_ECP_C
 #define MBEDTLS_BIGNUM_C
-#endif /* !MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_PUBLIC_KEY */
 #endif /* PSA_WANT_KEY_TYPE_ECC_PUBLIC_KEY */
 
 #if defined(PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_BASIC)
-#if !defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR_BASIC)
 #define MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_BASIC 1
-#endif /* !MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR_BASIC */
+#define MBEDTLS_ECP_C
+#define MBEDTLS_BIGNUM_C
 #endif /* PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_BASIC */
 
 #if defined(PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_IMPORT)
-#if !defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR_IMPORT)
 #define MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_IMPORT 1
-#endif /* !MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR_IMPORT */
+#define MBEDTLS_ECP_C
+#define MBEDTLS_BIGNUM_C
 #endif /* PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_IMPORT */
 
 #if defined(PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_EXPORT)
-#if !defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR_EXPORT)
 #define MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_EXPORT 1
-#endif /* !MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR_EXPORT */
+#define MBEDTLS_ECP_C
+#define MBEDTLS_BIGNUM_C
 #endif /* PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_EXPORT */
 
 #if defined(PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_GENERATE)
-#if !defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR_GENERATE)
 #define MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_GENERATE 1
-#endif /* !MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR_GENERATE */
+#define MBEDTLS_ECP_C
+#define MBEDTLS_BIGNUM_C
 #endif /* PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_GENERATE */
 
 #if defined(PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_DERIVE)
-#if !defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR_DERIVE)
 #define MBEDTLS_PSA_BUILTIN_KEY_TYPE_ECC_KEY_PAIR_DERIVE 1
+#define MBEDTLS_ECP_C
+#define MBEDTLS_BIGNUM_C
 #endif /* !MBEDTLS_PSA_ACCEL_KEY_TYPE_ECC_KEY_PAIR_DERIVE */
-#endif /* PSA_WANT_KEY_TYPE_ECC_KEY_PAIR_DERIVE */
+
+#endif /* MBEDTLS_PSA_ECC_ACCEL_INCOMPLETE */
 
 #if defined(PSA_WANT_ALG_FFDH)
 #if !defined(MBEDTLS_PSA_ACCEL_ALG_FFDH)