Arduino UNO: force USE_CERT_BUFFERS_256 to fit in flash

Fixes failing CI test

Author: danielinux

examples/configs/user_settings_arduino.h

@@ -180,6 +180,12 @@
         /* WOLFSSL_SEND_HRR_COOKIE is needed to use DTLS 1.3 server */
         #define WOLFSSL_SEND_HRR_COOKIE
     #endif
+#elif defined(ARDUINO_UNOR4_WIFI)
+    /*
+     * UNO R4 WiFi is now just over the flash limit in the client sketch.
+     * Use the smaller ECC-256 built-in cert set to keep the examples fitting.
+     */
+    #define USE_CERT_BUFFERS_256
 #elif defined (__AVR__) || defined(__AVR_ARCH__) || defined(__MEGAAVR__)
     /* Do not enable TLS on platforms without networking */
 
@@ -628,6 +634,25 @@
         #define CTX_SERVER_KEY       server_key_der_1024
         #define CTX_SERVER_KEY_SIZE  sizeof_server_key_der_1024
         #define CTX_SERVER_KEY_TYPE  WOLFSSL_FILETYPE_ASN1
+    #elif defined(USE_CERT_BUFFERS_256)
+        #include <wolfssl/certs_test.h>
+        #define CTX_CA_CERT          ca_ecc_cert_der_256
+        #define CTX_CA_CERT_SIZE     sizeof_ca_ecc_cert_der_256
+        #define CTX_CA_CERT_TYPE     WOLFSSL_FILETYPE_ASN1
+
+        #define CTX_CLIENT_CERT      cliecc_cert_der_256
+        #define CTX_CLIENT_CERT_SIZE sizeof_cliecc_cert_der_256
+        #define CTX_CLIENT_CERT_TYPE WOLFSSL_FILETYPE_ASN1
+        #define CTX_CLIENT_KEY       ecc_clikey_der_256
+        #define CTX_CLIENT_KEY_SIZE  sizeof_ecc_clikey_der_256
+        #define CTX_CLIENT_KEY_TYPE  WOLFSSL_FILETYPE_ASN1
+
+        #define CTX_SERVER_CERT      serv_ecc_der_256
+        #define CTX_SERVER_CERT_SIZE sizeof_serv_ecc_der_256
+        #define CTX_SERVER_CERT_TYPE WOLFSSL_FILETYPE_ASN1
+        #define CTX_SERVER_KEY       ecc_key_der_256
+        #define CTX_SERVER_KEY_SIZE  sizeof_ecc_key_der_256
+        #define CTX_SERVER_KEY_TYPE  WOLFSSL_FILETYPE_ASN1
     #else
         #define USE_CERT_BUFFERS_256
     #endif