diff --git a/nanomodbus.c b/nanomodbus.c
index 33226c9..409d54b 100644
--- a/nanomodbus.c
+++ b/nanomodbus.c
@@ -1277,21 +1277,21 @@ nmbs_error nmbs_write_multiple_registers(nmbs_t* nmbs, uint16_t address, uint16_
 #endif
 
 
-nmbs_error nmbs_send_raw_pdu(nmbs_t* nmbs, uint8_t fc, const void* data, uint16_t data_len) {
+nmbs_error nmbs_send_raw_pdu(nmbs_t* nmbs, uint8_t fc, const uint8_t* data, uint16_t data_len) {
     msg_state_req(nmbs, fc);
     put_msg_header(nmbs, data_len);
 
     DEBUG("raw ");
     for (uint16_t i = 0; i < data_len; i++) {
-        put_1(nmbs, ((const uint8_t*) (data))[i]);
-        DEBUG("%d ", ((const uint8_t*) (data))[i]);
+        put_1(nmbs, data[i]);
+        DEBUG("%d ", data[i]);
     }
 
     return send_msg(nmbs);
 }
 
 
-nmbs_error nmbs_receive_raw_pdu_response(nmbs_t* nmbs, void* data_out, uint16_t data_out_len) {
+nmbs_error nmbs_receive_raw_pdu_response(nmbs_t* nmbs, uint8_t* data_out, uint16_t data_out_len) {
     nmbs_error err = recv_res_header(nmbs);
     if (err != NMBS_ERROR_NONE)
         return err;
@@ -1301,7 +1301,7 @@ nmbs_error nmbs_receive_raw_pdu_response(nmbs_t* nmbs, void* data_out, uint16_t
         return err;
 
     for (uint16_t i = 0; i < data_out_len; i++) {
-        ((uint8_t*) (data_out))[i] = get_1(nmbs);
+        data_out[i] = get_1(nmbs);
     }
 
     err = recv_msg_footer(nmbs);
diff --git a/nanomodbus.h b/nanomodbus.h
index bad0f09..d828f99 100644
--- a/nanomodbus.h
+++ b/nanomodbus.h
@@ -393,7 +393,7 @@ nmbs_error nmbs_write_multiple_registers(nmbs_t* nmbs, uint16_t address, uint16_
  *
  * @return NMBS_ERROR_NONE if successful, other errors otherwise.
  */
-nmbs_error nmbs_send_raw_pdu(nmbs_t* nmbs, uint8_t fc, const void* data, uint16_t data_len);
+nmbs_error nmbs_send_raw_pdu(nmbs_t* nmbs, uint8_t fc, const uint8_t* data, uint16_t data_len);
 #endif
 
 #ifndef NMBS_CLIENT_DISABLED
@@ -404,7 +404,7 @@ nmbs_error nmbs_send_raw_pdu(nmbs_t* nmbs, uint8_t fc, const void* data, uint16_
  *
  * @return NMBS_ERROR_NONE if successful, other errors otherwise.
  */
-nmbs_error nmbs_receive_raw_pdu_response(nmbs_t* nmbs, void* data_out, uint16_t data_out_len);
+nmbs_error nmbs_receive_raw_pdu_response(nmbs_t* nmbs, uint8_t* data_out, uint16_t data_out_len);
 #endif
 
 /** Calculate the Modbus CRC of some data.
diff --git a/tests/nanomodbus_tests.c b/tests/nanomodbus_tests.c
index e1c34e7..a18452c 100644
--- a/tests/nanomodbus_tests.c
+++ b/tests/nanomodbus_tests.c
@@ -215,15 +215,15 @@ void test_fc1(nmbs_transport transport) {
     expect(nmbs_read_coils(&CLIENT, 65530, 7, NULL) == NMBS_ERROR_INVALID_ARGUMENT);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_VALUE from server when calling with quantity 0");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(1), htons(0)}, 4));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(1), htons(0)}, 4));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_VALUE);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_VALUE from server when calling with quantity > 2000");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(1), htons(2001)}, 4));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(1), htons(2001)}, 4));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_VALUE);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_ADDRESS from server when calling with address + quantity > 0xFFFF + 1");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(65530), htons(7)}, 4));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(65530), htons(7)}, 4));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_ADDRESS);
 
     should("return NMBS_EXCEPTION_SERVER_DEVICE_FAILURE when server handler returns any non-exception error");
@@ -282,15 +282,15 @@ void test_fc2(nmbs_transport transport) {
     expect(nmbs_read_discrete_inputs(&CLIENT, 65530, 7, NULL) == NMBS_ERROR_INVALID_ARGUMENT);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_VALUE from server when calling with quantity 0");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(1), htons(0)}, 4));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(1), htons(0)}, 4));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_VALUE);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_VALUE from server when calling with quantity > 2000");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(1), htons(2001)}, 4));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(1), htons(2001)}, 4));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_VALUE);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_ADDRESS from server when calling with address + quantity > 0xFFFF + 1");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(65530), htons(7)}, 4));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(65530), htons(7)}, 4));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_ADDRESS);
 
     should("return NMBS_EXCEPTION_SERVER_DEVICE_FAILURE when server handler returns any non-exception error");
@@ -371,15 +371,15 @@ void test_fc3(nmbs_transport transport) {
     expect(nmbs_read_holding_registers(&CLIENT, 0xFFFF, 2, NULL) == NMBS_ERROR_INVALID_ARGUMENT);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_VALUE from server when calling with quantity 0");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(1), htons(0)}, 4));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(1), htons(0)}, 4));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_VALUE);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_VALUE from server when calling with quantity > 2000");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(1), htons(2001)}, 4));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(1), htons(2001)}, 4));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_VALUE);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_ADDRESS from server when calling with address + quantity > 0xFFFF + 1");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(0xFFFF), htons(2)}, 4));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(0xFFFF), htons(2)}, 4));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_ADDRESS);
 
     should("return NMBS_EXCEPTION_SERVER_DEVICE_FAILURE when server handler returns any non-exception error");
@@ -426,15 +426,15 @@ void test_fc4(nmbs_transport transport) {
     expect(nmbs_read_input_registers(&CLIENT, 0xFFFF, 2, NULL) == NMBS_ERROR_INVALID_ARGUMENT);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_VALUE from server when calling with quantity 0");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(1), htons(0)}, 4));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(1), htons(0)}, 4));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_VALUE);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_VALUE from server when calling with quantity > 2000");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(1), htons(2001)}, 4));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(1), htons(2001)}, 4));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_VALUE);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_ADDRESS from server when calling with address + quantity > 0xFFFF + 1");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(0xFFFF), htons(2)}, 4));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(0xFFFF), htons(2)}, 4));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_ADDRESS);
 
     should("return NMBS_EXCEPTION_SERVER_DEVICE_FAILURE when server handler returns any non-exception error");
@@ -494,10 +494,10 @@ void test_fc5(nmbs_transport transport) {
     start_client_and_server(transport, &(nmbs_callbacks){.write_single_coil = write_coil});
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_VALUE when calling with value !0x0000 or 0xFF000");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(6), htons(0x0001)}, 4));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(6), htons(0x0001)}, 4));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_VALUE);
 
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(6), htons(0xFFFF)}, 4));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(6), htons(0xFFFF)}, 4));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_VALUE);
 
     should("return NMBS_EXCEPTION_SERVER_DEVICE_FAILURE when server handler returns any non-exception error");
@@ -514,7 +514,7 @@ void test_fc5(nmbs_transport transport) {
     check(nmbs_write_single_coil(&CLIENT, 5, false));
 
     should("echo request's address and value");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(4), htons(0xFF00)}, 4));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(4), htons(0xFF00)}, 4));
     check(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 4));
 
     expect(((uint16_t*) raw_res)[0] == ntohs(4));
@@ -574,7 +574,7 @@ void test_fc6(nmbs_transport transport) {
     check(nmbs_write_single_register(&CLIENT, 5, false));
 
     should("echo request's address and value");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(4), htons(0x123)}, 4));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(4), htons(0x123)}, 4));
     check(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 4));
 
     expect(((uint16_t*) raw_res)[0] == ntohs(4));
@@ -653,15 +653,15 @@ void test_fc15(nmbs_transport transport) {
     expect(nmbs_write_multiple_coils(&CLIENT, 0xFFFF, 2, bf) == NMBS_ERROR_INVALID_ARGUMENT);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_VALUE from server when calling with quantity 0");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(1), htons(0), htons(0x0100)}, 6));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(1), htons(0), htons(0x0100)}, 6));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_VALUE);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_VALUE from server when calling with quantity > 2000");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(1), htons(2000), htons(0x0100)}, 6));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(1), htons(2000), htons(0x0100)}, 6));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_VALUE);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_ADDRESS from server when calling with address + quantity > 0xFFFF + 1");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(0xFFFF), htons(2), htons(0x0100)}, 6));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(0xFFFF), htons(2), htons(0x0100)}, 6));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_ADDRESS);
 
     /*
@@ -690,7 +690,7 @@ void test_fc15(nmbs_transport transport) {
     check(nmbs_write_multiple_coils(&CLIENT, 5, 27, bf));
 
     should("echo request's address and value");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(7), htons(1), htons(0x0100)}, 6));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(7), htons(1), htons(0x0100)}, 6));
     check(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 4));
 
     expect(((uint16_t*) raw_res)[0] == ntohs(7));
@@ -769,15 +769,15 @@ void test_fc16(nmbs_transport transport) {
     expect(nmbs_write_multiple_registers(&CLIENT, 0xFFFF, 2, registers) == NMBS_ERROR_INVALID_ARGUMENT);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_VALUE from server when calling with quantity 0");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(1), htons(0), htons(0x0200), htons(0)}, 7));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(1), htons(0), htons(0x0200), htons(0)}, 7));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_VALUE);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_VALUE from server when calling with quantity > 2000");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(1), htons(2000), htons(0x0200), htons(0)}, 7));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(1), htons(2000), htons(0x0200), htons(0)}, 7));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_VALUE);
 
     should("return NMBS_EXCEPTION_ILLEGAL_DATA_ADDRESS from server when calling with address + quantity > 0xFFFF + 1");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(0xFFFF), htons(2), htons(0x0200), htons(0)}, 7));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(0xFFFF), htons(2), htons(0x0200), htons(0)}, 7));
     expect(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 2) == NMBS_EXCEPTION_ILLEGAL_DATA_ADDRESS);
 
     /*
@@ -806,7 +806,7 @@ void test_fc16(nmbs_transport transport) {
     check(nmbs_write_multiple_registers(&CLIENT, 6, 27, registers));
 
     should("echo request's address and value");
-    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(7), htons(1), htons(0x0200), htons(0)}, 7));
+    check(nmbs_send_raw_pdu(&CLIENT, fc, (uint8_t*) (uint16_t[]){htons(7), htons(1), htons(0x0200), htons(0)}, 7));
     check(nmbs_receive_raw_pdu_response(&CLIENT, raw_res, 4));
 
     expect(((uint16_t*) raw_res)[0] == ntohs(7));