diff --git a/bootloader.c b/bootloader.c
index b3ce05e..71cd22f 100644
--- a/bootloader.c
+++ b/bootloader.c
@@ -24,7 +24,6 @@ error_code status;
 char okk[4] = "OK\r\n";
 char errr[5] = "ERR\r\n";
 
-char buff[256];
 
 
 
@@ -39,37 +38,40 @@ crc_t crc_prog, crc_data;
 
 // TODO: insert other definitions and declarations here
 
+char buff[256];
 int main(void) {
     uart_init(115200);
-    //iap_read_part_id();
-    //iap_copy_to_flash(0x8000,(uint8_t*)test, 4);
     while(1){
 		uart_receive_command(buff);
 		uart_parse_command(buff, &cmd);
-		if (strcmp("GETID", cmd.argv[0])==0){
+		if (strncmp("GETID", cmd.argv[0], 5)==0){
 			uart_commands_getid(&status);
-		}else if(strcmp("GETSERIAL", cmd.argv[0])==0){
+
+		}else if(strncmp("GETSE", cmd.argv[0], 5)==0){
 			uart_commands_getserial(&status);
-		}else if(strcmp("PROG", cmd.argv[0])==0){
+
+		}else if(strncmp("PROG", cmd.argv[0], 4)==0){
 			crc_prog = uart_string_to_int(cmd.argv[3]);
 			total_size = uart_string_to_int(cmd.argv[2]);
 			offset = uart_string_to_int(cmd.argv[1]);
 			crc_data = uart_commands_prog();
 			offset_pointer = offset;
+
 		}else if(strcmp("DATA", cmd.argv[0])==0){
 			int size = uart_string_to_int(cmd.argv[1]);
 			crc_t local_checksum = uart_string_to_int(cmd.argv[2]);
 			uart_commands_data(&status, size, &crc_data, local_checksum, offset_pointer);
 			if(status == 0) offset_pointer += size;
+
 		}else if(strcmp("CHECK", cmd.argv[0])==0){
-			if(crc_prog == crc_data){
+			error_code is_error = uart_commands_check(crc_prog, crc_data);
+			if(is_error == ok){
 				uart_send(okk, 5);
 			}else{
 				uart_send(errr, 6);
 			}
-		}
 
-		//uart_commands_data(&status, 0x00004000, 0x00048f40, 0x4);
+		}
     }
     while(1);
     return 0 ;
diff --git a/iap.c b/iap.c
index 5e49178..2b2e22f 100644
--- a/iap.c
+++ b/iap.c
@@ -77,7 +77,7 @@ void iap_erase_sectors(error_code* status, int start, int end){
 
 uint32_t iap_read_part_id(error_code* status){
     //iap_prepare_sectors(dst_flash, dst_flash+num_bytes-1);
-	iap_prepare_sectors(status, 2, 9);
+	iap_prepare_sectors(status, 2, 10);
     command[0] = 54;
     iap_entry_wrapped();
         if(output[0] == IAP_CMD_SUCCESS) {
@@ -109,7 +109,7 @@ void iap_copy_to_flash(error_code* status, int dst_flash, uint32_t* src_ram, int
 }
 
 void iap_read_serial(error_code* status, uint32_t* res){
-    iap_prepare_sectors(status, 2, 9);
+    //iap_prepare_sectors(status, 2, 9);
     command[0] = 58;
     iap_entry_wrapped();
         if(output[0] == IAP_CMD_SUCCESS) {
diff --git a/uart.c b/uart.c
index 7923f1d..5559b9c 100644
--- a/uart.c
+++ b/uart.c
@@ -45,14 +45,17 @@ void uart_send(char* buff, uint32_t length){
 
 void uart_receive_command(char* chara){
 	char* curr = chara;
-    while(strncmp(curr, "\r\n", 2) != 0){
+    //while(strncmp("\r\n",curr, 2) != 0){
+	while(*curr != '\n'){
         while(((LPC_UART0->LSR)&(1)) == 0);
         *curr = LPC_UART0->RBR;
-        if(strncmp(curr, "\r\n", 2) != 0) curr++;
+        //if(strncmp("\r\n",curr, 2) != 0) curr++;
+        if((*curr != '\n')) curr++;
     }
 }
 
 void uart_receive_data(uint8_t* chara){
+	//size parameter add while size != size_given
 	uint8_t* curr = chara;
     while(*curr != '\0'){
         while(((LPC_UART0->LSR)&(1)) == 0);
diff --git a/uart_commands.c b/uart_commands.c
index fef33a4..acce2bb 100644
--- a/uart_commands.c
+++ b/uart_commands.c
@@ -2,16 +2,16 @@
 
 static uint8_t data[4096];
 
-char OK[4] = "OK\r\n";
-char ERR[5] = "ERR\r\n";
+char OK[5] = "OK\r\n";
+char ERR[6] = "ERR\r\n";
 
 void uart_commands_getid(error_code* status){
     char hex[15];
     uint32_t res = iap_read_part_id(status);
     sprintf(hex, "0x%x\r\n", res);
     if(*status == 0){
-        uart_send(OK, 5);
-        uart_send(hex, 12);
+        uart_send(OK, strlen(OK));
+        uart_send(hex, strlen(hex));
     }
 }
 
@@ -22,7 +22,7 @@ void uart_commands_getserial(error_code* status){
     iap_read_serial(status, res);
     sprintf(hex, "0x%x%x%x%x\r\n", res[0], res[1], res[2], res[3]);
     if(*status == 0){
-        uart_send(OK, 5);
+        uart_send(OK, 4);
         uart_send(hex, 35);
     }
 }
@@ -32,7 +32,7 @@ crc_t uart_commands_prog(void){
 	uart_send(OK, 5);
 }
 
-void uart_commands_data(error_code* status, int size, crc_t* checksum_global, crc_t checksum_loc, int offset){
+error_code uart_commands_data(error_code* status, int size, crc_t* checksum_global, crc_t checksum_loc, int offset){
 	uart_receive_data(data);
 	crc_t checksum_tmp = crc_init();
 	checksum_tmp = crc_update(checksum_tmp, data, size);
@@ -67,11 +67,18 @@ void uart_commands_data(error_code* status, int size, crc_t* checksum_global, cr
 			tmp = tmp - 256;
 		}
 		*checksum_global = crc_update(*checksum_global, data, size);
+		return ok;
 	}else{
 		uart_send(ERR, 6);
+		return local_checksum;
 	}
 }
 
+error_code uart_commands_check(crc_t crc_received, crc_t crc_calculated){
+	if(crc_received == crc_calculated) return ok;
+	else return global_checksum;
+}
+
 
 //  return: -1 in case of ERR otherwise 0.
 int uart_parse_command(char *user_input, cmd_t *cmd) {
@@ -100,6 +107,7 @@ int uart_parse_command(char *user_input, cmd_t *cmd) {
 
 uint32_t uart_string_to_int(const char *str) {
     // Convert input in port number
-    unsigned long int hex = strtoul(str, NULL, 16);
+	char* tmp;
+    unsigned long int hex = strtoul(str, tmp, 16);
     return hex;
 }
diff --git a/uart_commands.h b/uart_commands.h
index 840b701..29f959c 100644
--- a/uart_commands.h
+++ b/uart_commands.h
@@ -6,7 +6,7 @@
 #include "iap.h"
 #include "crc.h"
 
-#define  DELIMIERS ","
+#define  DELIMIERS ','
 
 
 
@@ -23,7 +23,9 @@ void uart_commands_getserial(error_code* status);
 
 crc_t uart_commands_prog(void);
 
-void uart_commands_data(error_code* status, int size, crc_t* checksum_global, crc_t checksum_loc, int offset);
+error_code uart_commands_data(error_code* status, int size, crc_t* checksum_global, crc_t checksum_loc, int offset);
+
+error_code uart_commands_check(crc_t crc_received, crc_t crc_calculated);
 
 int uart_parse_command(char *user_input, cmd_t *cmd);