diff --git a/util.cpp b/util.cpp
index 05c5f8e..7ffde4f 100644
--- a/util.cpp
+++ b/util.cpp
@@ -272,23 +272,6 @@ static size_t all_data_cb(const void *ptr, size_t size, size_t nmemb,
 	return len;
 }
 
-static size_t upload_data_cb(void *ptr, size_t size, size_t nmemb,
-			     void *user_data)
-{
-	struct upload_buffer *ub = (struct upload_buffer *)user_data;
-	unsigned int len = (unsigned int)(size * nmemb);
-
-	if (len > ub->len - ub->pos)
-		len = (unsigned int)(ub->len - ub->pos);
-
-	if (len) {
-		memcpy(ptr, (char*)ub->buf + ub->pos, len);
-		ub->pos += len;
-	}
-
-	return len;
-}
-
 #if LIBCURL_VERSION_NUM >= 0x071200
 static int seek_data_cb(void *user_data, curl_off_t offset, int origin)
 {
@@ -429,7 +412,6 @@ static json_t *json_rpc_call(CURL *curl, const char *url,
 	json_t *val, *err_val, *res_val;
 	int rc;
 	struct data_buffer all_data = { 0 };
-	struct upload_buffer upload_data;
 	json_error_t err;
 	struct curl_slist *headers = NULL;
 	char *httpdata;
@@ -455,10 +437,12 @@ static json_t *json_rpc_call(CURL *curl, const char *url,
 	curl_easy_setopt(curl, CURLOPT_TCP_NODELAY, 1);
 	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, all_data_cb);
 	curl_easy_setopt(curl, CURLOPT_WRITEDATA, &all_data);
-	curl_easy_setopt(curl, CURLOPT_READFUNCTION, upload_data_cb);
-	curl_easy_setopt(curl, CURLOPT_READDATA, &upload_data);
 #if LIBCURL_VERSION_NUM >= 0x071200
 	curl_easy_setopt(curl, CURLOPT_SEEKFUNCTION, &seek_data_cb);
+	struct upload_buffer upload_data;
+	upload_data.buf = rpc_req;
+	upload_data.len = strlen(rpc_req);
+	upload_data.pos = 0;
 	curl_easy_setopt(curl, CURLOPT_SEEKDATA, &upload_data);
 #endif
 	curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, curl_err_str);
@@ -479,14 +463,12 @@ static json_t *json_rpc_call(CURL *curl, const char *url,
 		curl_easy_setopt(curl, CURLOPT_SOCKOPTFUNCTION, sockopt_keepalive_cb);
 #endif
 	curl_easy_setopt(curl, CURLOPT_POST, 1);
+	curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, strlen (rpc_req));
+    curl_easy_setopt(curl, CURLOPT_POSTFIELDS, rpc_req);
 
 	if (opt_protocol)
 		applog(LOG_DEBUG, "JSON protocol request:\n%s", rpc_req);
 
-	upload_data.buf = rpc_req;
-	upload_data.len = strlen(rpc_req);
-	upload_data.pos = 0;
-	sprintf(len_hdr, "Content-Length: %lu", (unsigned long) upload_data.len);
 	sprintf(hashrate_hdr, "X-Mining-Hashrate: %llu", (unsigned long long) global_hashrate);
 
 	headers = curl_slist_append(headers, "Content-Type: application/json");