diff --git a/include/mbedtls/config_adjust_legacy_from_psa.h b/include/mbedtls/config_adjust_legacy_from_psa.h
index 8d864ab6d..471ba181b 100644
--- a/include/mbedtls/config_adjust_legacy_from_psa.h
+++ b/include/mbedtls/config_adjust_legacy_from_psa.h
@@ -67,6 +67,10 @@
 
 #if defined(PSA_WANT_ALG_HKDF)
 #if !defined(MBEDTLS_PSA_ACCEL_ALG_HKDF)
+/*
+ * The PSA implementation has its own implementation of HKDF, separate from
+ * hkdf.c. No need to enable MBEDTLS_HKDF_C here.
+ */
 #define MBEDTLS_PSA_BUILTIN_ALG_HMAC 1
 #define MBEDTLS_PSA_BUILTIN_ALG_HKDF 1
 #endif /* !MBEDTLS_PSA_ACCEL_ALG_HKDF */
@@ -74,6 +78,10 @@
 
 #if defined(PSA_WANT_ALG_HKDF_EXTRACT)
 #if !defined(MBEDTLS_PSA_ACCEL_ALG_HKDF_EXTRACT)
+/*
+ * The PSA implementation has its own implementation of HKDF, separate from
+ * hkdf.c. No need to enable MBEDTLS_HKDF_C here.
+ */
 #define MBEDTLS_PSA_BUILTIN_ALG_HMAC 1
 #define MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXTRACT 1
 #endif /* !MBEDTLS_PSA_ACCEL_ALG_HKDF_EXTRACT */
@@ -81,6 +89,10 @@
 
 #if defined(PSA_WANT_ALG_HKDF_EXPAND)
 #if !defined(MBEDTLS_PSA_ACCEL_ALG_HKDF_EXPAND)
+/*
+ * The PSA implementation has its own implementation of HKDF, separate from
+ * hkdf.c. No need to enable MBEDTLS_HKDF_C here.
+ */
 #define MBEDTLS_PSA_BUILTIN_ALG_HMAC 1
 #define MBEDTLS_PSA_BUILTIN_ALG_HKDF_EXPAND 1
 #endif /* !MBEDTLS_PSA_ACCEL_ALG_HKDF_EXPAND */
diff --git a/library/pkwrite.c b/library/pkwrite.c
index 439428cff..eee64ab17 100644
--- a/library/pkwrite.c
+++ b/library/pkwrite.c
@@ -77,7 +77,7 @@ static inline int mbedtls_pk_is_rfc8410(const mbedtls_pk_context *pk)
     return 0;
 }
 
-#if defined(MBEDTLS_USE_PSA_CRYPTO)
+#if defined(MBEDTLS_USE_PSA_CRYPTO) && defined(MBEDTLS_PEM_WRITE_C)
 /* It is assumed that the input key is opaque */
 static psa_ecc_family_t pk_get_opaque_ec_family(const mbedtls_pk_context *pk)
 {
@@ -92,7 +92,7 @@ static psa_ecc_family_t pk_get_opaque_ec_family(const mbedtls_pk_context *pk)
 
     return ec_family;
 }
-#endif /* MBETLS_USE_PSA_CRYPTO */
+#endif /* MBETLS_USE_PSA_CRYPTO && MBEDTLS_PEM_WRITE_C */
 #endif /* MBEDTLS_PK_HAVE_RFC8410_CURVES */
 #endif /* MBEDTLS_PK_HAVE_ECC_KEYS */