diff --git a/F1-nolib/chronometer/GPS.c b/F1-nolib/chronometer/GPS.c
index 0a0454c..ad6cb66 100644
--- a/F1-nolib/chronometer/GPS.c
+++ b/F1-nolib/chronometer/GPS.c
@@ -149,7 +149,9 @@ void GPS_send_start_seq(){
  */
 void GPS_parse_answer(const char *buf){
     char *ptr;
-    DBG(buf);
+#if defined USART1PROXY
+    usart_send(1, buf); newline();
+#endif
     if(buf[1] == 'P') return; // answers to proprietary messages
     if(cmpstr(buf+3, "RMC", 3)){ // not RMC message
         need2startseq = 1;
diff --git a/F1-nolib/chronometer/Makefile b/F1-nolib/chronometer/Makefile
index 76dd294..d253d7a 100644
--- a/F1-nolib/chronometer/Makefile
+++ b/F1-nolib/chronometer/Makefile
@@ -12,6 +12,8 @@ LDSCRIPT	?= stm32f103x8.ld
 DEFS		= -DVERSION=\"0.0.1\"
 # debug
 DEFS		+= -DEBUG
+# proxy GPS output over USART1
+DEFS += -DUSART1PROXY
 
 INDEPENDENT_HEADERS=
 
diff --git a/F1-nolib/chronometer/Readme.md b/F1-nolib/chronometer/Readme.md
index c37bb0b..3bf8cfb 100644
--- a/F1-nolib/chronometer/Readme.md
+++ b/F1-nolib/chronometer/Readme.md
@@ -11,7 +11,7 @@ Chronometer for downhill competitions
 
 - PB8, PB9 - onboard LEDs
 
-- PA4  - TRIG2 - 12V trigger (EXTI)
+- PA4  - TRIG2 - 12V trigger (EXTI)  -- not implemented yet
 - PA13 - TRIG0 - button0 (EXTI)
 - PA14 - TRIG1 - button1/laser/etc (EXTI)
 - PA15 - USB pullup
diff --git a/F1-nolib/chronometer/chrono.bin b/F1-nolib/chronometer/chrono.bin
index 9d8617c..2f8e1f6 100755
Binary files a/F1-nolib/chronometer/chrono.bin and b/F1-nolib/chronometer/chrono.bin differ
diff --git a/F1-nolib/chronometer/flash.c b/F1-nolib/chronometer/flash.c
new file mode 100644
index 0000000..0a5d25b
--- /dev/null
+++ b/F1-nolib/chronometer/flash.c
@@ -0,0 +1,240 @@
+/*
+ *                                                                                                  geany_encoding=koi8-r
+ * flash.c
+ *
+ * Copyright 2017 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ *
+ */
+
+/**
+  ATTENTION!!
+  This things works only if you will add next section:
+
+    .myvars :
+    {
+     . = ALIGN(1024);
+     KEEP(*(.myvars))
+    } > rom
+
+  after section .data
+*/
+
+#include "stm32f1.h"
+#include <string.h> // memcpy
+
+#include "flash.h"
+#include "lidar.h"
+#ifdef EBUG
+#include "usart.h"
+#endif
+
+extern uint32_t _edata, _etext, _sdata;
+static int maxnum = FLASH_BLOCK_SIZE / sizeof(user_conf);
+
+
+typedef struct{
+	const user_conf all_stored;
+} flash_storage;
+
+#define USERCONF_INITIALIZER  { \
+	.userconf_sz = sizeof(user_conf)	\
+	,.dist_min = LIDAR_MIN_DIST			\
+	,.dist_max = LIDAR_MAX_DIST			\
+	}
+
+__attribute__((section(".myvars"))) static const flash_storage Flash_Storage = {
+	.all_stored = USERCONF_INITIALIZER
+};
+
+static const user_conf *Flash_Data = &Flash_Storage.all_stored;
+
+user_conf the_conf = USERCONF_INITIALIZER;
+
+static int erase_flash();
+
+static int currentconfidx = -1; // index of current configuration
+
+/**
+ * @brief binarySearch - binary search in flash for last non-empty cell
+ * @param l - left index
+ * @param r - right index (should be @1 less than last index!)
+ * @return index of non-empty cell or -1
+ */
+static int binarySearch(int l, int r){
+    while(r >= l){
+        int mid = l + (r - l) / 2;
+        // If the element is present at the middle
+        // itself
+        uint16_t sz = Flash_Data[mid].userconf_sz;
+        if(sz == sizeof(user_conf)){
+            if(Flash_Data[mid+1].userconf_sz == 0xffff){
+#if 0
+        SEND("Found at "); printu(1, mid); newline();
+#endif
+                return mid;
+            }else{ // element is to the right
+                l = mid + 1;
+#if 0
+        SEND("To the right, L="); printu(1, l); newline();
+#endif
+            }
+        }else{ // element is to the left
+            r = mid - 1;
+#if 0
+        SEND("To the left, R="); printu(1, r); newline();
+#endif
+        }
+    }
+    DBG("Not found!");
+    return -1; // not found
+}
+
+static int get_gooddata(){
+    static uint8_t firstrun = 1;
+    if(firstrun){
+        firstrun = 0;
+        if(FLASH_SIZE > 0 && FLASH_SIZE < 20000){
+            uint32_t flsz = FLASH_SIZE * 1024; // size in bytes
+            flsz -= (uint32_t)Flash_Data - FLASH_BASE;
+#if 0
+            SEND("All size: "); printu(1, flsz); newline();
+#endif
+            uint32_t usz = (sizeof(user_conf) + 1) / 2;
+            maxnum = flsz / 2 / usz;
+#if 0
+            SEND("Maxnum: "); printu(1, maxnum); newline();
+#endif
+        }
+    }
+    return binarySearch(0, maxnum-2); // -1 if there's no data at all & flash is clear; maxnum-1 if flash is full
+}
+
+void get_userconf(){
+    const user_conf *c = Flash_Data;
+    int idx = get_gooddata();
+    if(idx < 0) return; // no data stored
+    currentconfidx = idx;
+    memcpy(&the_conf, &c[idx], sizeof(user_conf));
+}
+
+// store new configuration
+// @return 0 if all OK
+int store_userconf(){
+    IWDG->KR = IWDG_REFRESH;
+    int ret = 0;
+    const user_conf *c = Flash_Data;
+    int idx = currentconfidx;
+    // maxnum - 3 means that there always should be at least one empty record after last data
+    if(idx < 0 || idx > maxnum - 3){ // data corruption or there's no more place
+        idx = 0;
+        DBG("Need to erase flash!");
+        if(erase_flash()) return 1;
+    }else ++idx; // take next data position
+    currentconfidx = idx;
+    if (FLASH->CR & FLASH_CR_LOCK){ // unloch flash
+        FLASH->KEYR = FLASH_KEY1;
+        FLASH->KEYR = FLASH_KEY2;
+    }
+    while (FLASH->SR & FLASH_SR_BSY);
+    if(FLASH->SR & FLASH_SR_WRPRTERR) return 1; // write protection
+    FLASH->SR = FLASH_SR_EOP | FLASH_SR_PGERR | FLASH_SR_WRPRTERR; // clear all flags
+    FLASH->CR |= FLASH_CR_PG;
+    uint16_t *data = (uint16_t*) &the_conf;
+    uint16_t *address = (uint16_t*) &c[idx];
+    uint32_t i, count = (sizeof(user_conf) + 1) / 2;
+    for (i = 0; i < count; ++i){
+        *(volatile uint16_t*)(address + i) = data[i];
+        while (FLASH->SR & FLASH_SR_BSY);
+        if(FLASH->SR &  FLASH_SR_PGERR) ret = 1; // program error - meet not 0xffff
+        else while (!(FLASH->SR & FLASH_SR_EOP));
+        FLASH->SR = FLASH_SR_EOP | FLASH_SR_PGERR | FLASH_SR_WRPRTERR;
+    }
+    FLASH->CR &= ~(FLASH_CR_PG);
+    return ret;
+}
+
+static int erase_flash(){
+    int ret = 0;
+    uint32_t nblocks = 1;
+    if(FLASH_SIZE > 0 && FLASH_SIZE < 20000){
+        uint32_t flsz = FLASH_SIZE * 1024; // size in bytes
+        flsz -= (uint32_t)Flash_Data - FLASH_BASE;
+        nblocks = flsz / FLASH_BLOCK_SIZE;
+#if 0
+        SEND("N blocks:"); printu(1, nblocks); newline();
+#endif
+    }
+    for(uint32_t i = 0; i < nblocks; ++i){
+        IWDG->KR = IWDG_REFRESH;
+        /* (1) Wait till no operation is on going */
+        /* (2) Clear error & EOP bits */
+        /* (3) Check that the Flash is unlocked */
+        /* (4) Perform unlock sequence */
+        while ((FLASH->SR & FLASH_SR_BSY) != 0){} /* (1) */
+        FLASH->SR = FLASH_SR_EOP | FLASH_SR_PGERR | FLASH_SR_WRPRTERR;  /* (2) */
+      /*  if (FLASH->SR & FLASH_SR_EOP){
+            FLASH->SR |= FLASH_SR_EOP;
+        }*/
+        if ((FLASH->CR & FLASH_CR_LOCK) != 0){ /* (3) */
+            FLASH->KEYR = FLASH_KEY1; /* (4) */
+            FLASH->KEYR = FLASH_KEY2;
+        }
+        /* (1) Set the PER bit in the FLASH_CR register to enable page erasing */
+        /* (2) Program the FLASH_AR register to select a page to erase */
+        /* (3) Set the STRT bit in the FLASH_CR register to start the erasing */
+        /* (4) Wait until the  EOP flag in the FLASH_SR register set */
+        /* (5) Clear EOP flag by software by writing EOP at 1 */
+        /* (6) Reset the PER Bit to disable the page erase */
+        FLASH->CR |= FLASH_CR_PER; /* (1) */
+#if 0
+        SEND("Delete block number "); printu(1, i); newline();
+#endif
+        FLASH->AR = (uint32_t)Flash_Data + i*FLASH_BLOCK_SIZE; /* (2) */
+        FLASH->CR |= FLASH_CR_STRT; /* (3) */
+        while(!(FLASH->SR & FLASH_SR_EOP));
+        FLASH->SR |= FLASH_SR_EOP; /* (5)*/
+        if(FLASH->SR & FLASH_SR_WRPRTERR){ /* Check Write protection error */
+            ret = 1;
+            DBG("Write protection error!");
+            FLASH->SR |= FLASH_SR_WRPRTERR; /* Clear the flag by software by writing it at 1*/
+            break;
+        }
+        FLASH->CR &= ~FLASH_CR_PER; /* (6) */
+    }
+    return ret;
+}
+
+#ifdef EBUG
+void dump_userconf(){
+    SEND("userconf_sz="); printu(1, the_conf.userconf_sz); newline();
+    SEND("dist_min="); printu(1, the_conf.dist_min); newline();
+    SEND("dist_max="); printu(1, the_conf.dist_max); newline();
+}
+
+void addNrecs(int N){
+    SEND("Try to store userconf for "); printu(1, N); SEND(" times\n");
+    for(int i = 0; i < N; ++i){
+        if(store_userconf()){
+            SEND("Error @ "); printu(1, i); newline();
+            return;
+        }
+    }
+    SEND("Curr idx: "); printu(1, currentconfidx); newline();
+}
+
+#endif
diff --git a/F1-nolib/chronometer/flash.h b/F1-nolib/chronometer/flash.h
new file mode 100644
index 0000000..8b2bd83
--- /dev/null
+++ b/F1-nolib/chronometer/flash.h
@@ -0,0 +1,48 @@
+/*
+ * flash.h
+ *
+ * Copyright 2017 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ *
+ */
+
+#pragma once
+#ifndef __FLASH_H__
+#define __FLASH_H__
+
+#include <stm32f1.h>
+
+#define FLASH_BLOCK_SIZE    (1024)
+#define FLASH_SIZE_REG      ((uint32_t)0x1FFFF7E0)
+#define FLASH_SIZE          *((uint16_t*)FLASH_SIZE_REG)
+
+typedef struct{
+    uint16_t userconf_sz;       // "magick number"
+    uint32_t dist_min;          // minimal distance for LIDAR
+    uint32_t dist_max;          // maximal -//-
+} user_conf;
+
+extern user_conf the_conf;
+
+void get_userconf();
+int store_userconf();
+#ifdef EBUG
+void dump_userconf();
+void addNrecs(int N);
+#endif
+
+#endif // __FLASH_H__
diff --git a/F1-nolib/chronometer/hardware.c b/F1-nolib/chronometer/hardware.c
index 57d32ca..22b4f60 100644
--- a/F1-nolib/chronometer/hardware.c
+++ b/F1-nolib/chronometer/hardware.c
@@ -23,6 +23,7 @@
 
 #include "adc.h"
 #include "hardware.h"
+#include "time.h"
 #include "usart.h"
 
 static inline void gpio_setup(){
@@ -30,10 +31,10 @@ static inline void gpio_setup(){
     RCC->APB2ENR |= RCC_APB2ENR_IOPAEN | RCC_APB2ENR_IOPBEN | RCC_APB2ENR_IOPCEN | RCC_APB2ENR_AFIOEN;
     // turn off SWJ/JTAG
     AFIO->MAPR = AFIO_MAPR_SWJ_CFG_DISABLE;
-    // pullups
-    GPIOA->ODR = (1<<12)|(1<<13)|(1<<14);
-    // Set led (PB8) as opendrain output
-    GPIOB->CRH = CRH(8, CNF_ODOUTPUT|MODE_SLOW);
+    // pullups: PA1 - PPS, PA13/PA14 - buttons
+    GPIOA->ODR = (1<<12)|(1<<13)|(1<<14)|(1<<15);
+    // Set leds (PB8) as opendrain output
+    GPIOB->CRH = CRH(8, CNF_ODOUTPUT|MODE_SLOW) | CRH(9, CNF_ODOUTPUT|MODE_SLOW);
     // PPS pin (PA1) - input with weak pullup
     GPIOA->CRL = CRL(1, CNF_PUDINPUT|MODE_INPUT);
     // Set buttons (PA13/14) as inputs with weak pullups, USB pullup (PA15) - opendrain output
@@ -88,13 +89,8 @@ void hw_setup(){
 }
 
 void exti1_isr(){ // PPS - PA1
-    /*
-    if(trigger_ms[2] == DIDNT_TRIGGERED){ // prevent bounce
-        trigger_ms[2] = Timer;
-        memcpy(&trigger_time[2], &current_time, sizeof(curtime));
-    }
-    */
     DBG("exti1");
+    systick_correction();
     EXTI->PR = EXTI_PR_PR1;
 }
 
diff --git a/F1-nolib/chronometer/hardware.h b/F1-nolib/chronometer/hardware.h
index 0c9017e..cb2d123 100644
--- a/F1-nolib/chronometer/hardware.h
+++ b/F1-nolib/chronometer/hardware.h
@@ -35,10 +35,13 @@
 #define CMD_ADC1MAX     "adc1max"
 #define CMD_ADC2MAX     "adc2max"
 #define CMD_PRINTTIME   "time"
+#define CMD_STORECONF   "store"
 
-// onboard LED - PB8
-#define LED_port   GPIOB
-#define LED_pin    (1<<8)
+// onboard LEDs - PB8/PB9
+#define LED0_port   GPIOB
+#define LED0_pin    (1<<8)
+#define LED1_port   GPIOB
+#define LED1_pin    (1<<9)
 
 // PPS pin - PA1
 #define PPS_port    GPIOA
@@ -55,9 +58,12 @@
 #define USBPU_ON()  pin_clear(USBPU_port, USBPU_pin)
 #define USBPU_OFF() pin_set(USBPU_port, USBPU_pin)
 
-#define LED_blink()    pin_toggle(LED_port, LED_pin)
-#define LED_on()       pin_clear(LED_port, LED_pin)
-#define LED_off()      pin_set(LED_port, LED_pin)
+#define LED_blink()    pin_toggle(LED0_port, LED0_pin)
+#define LED_on()       pin_clear(LED0_port, LED0_pin)
+#define LED_off()      pin_set(LED0_port, LED0_pin)
+#define LED1_blink()   pin_toggle(LED1_port, LED1_pin)
+#define LED1_on()      pin_clear(LED1_port, LED1_pin)
+#define LED1_off()     pin_set(LED1_port, LED1_pin)
 
 // GPS USART == USART2, LIDAR USART == USART3
 #define GPS_USART   (2)
diff --git a/F1-nolib/chronometer/lidar.c b/F1-nolib/chronometer/lidar.c
index b21810c..dd2ee14 100644
--- a/F1-nolib/chronometer/lidar.c
+++ b/F1-nolib/chronometer/lidar.c
@@ -16,11 +16,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include "flash.h"
 #include "lidar.h"
 #include "usart.h"
 
-uint16_t lidar_max_dist = 100;
-uint16_t lidar_min_dist = 50;
 uint16_t last_lidar_dist = 0;
 uint16_t last_lidar_stren = 0;
 uint16_t lidar_triggered_dist = 0;
@@ -35,7 +34,7 @@ void parse_lidar_data(char *txt){
         return;
     }
     if(triggered){ // check if body gone
-        if(last_lidar_dist < lidar_min_dist || last_lidar_dist > lidar_max_dist || last_lidar_dist > lidar_triggered_dist + LIDAR_DIST_THRES){
+        if(last_lidar_dist < the_conf.dist_min || last_lidar_dist > the_conf.dist_max || last_lidar_dist > lidar_triggered_dist + LIDAR_DIST_THRES){
             triggered = 0;
 #ifdef EBUG
             SEND("Untriggered! distance=");
@@ -46,7 +45,7 @@ void parse_lidar_data(char *txt){
 #endif
         }
     }else{
-        if(last_lidar_dist > lidar_min_dist && last_lidar_dist < lidar_max_dist){
+        if(last_lidar_dist > the_conf.dist_min && last_lidar_dist < the_conf.dist_max){
             triggered = 1;
             lidar_triggered_dist = last_lidar_dist;
 #ifdef EBUG
diff --git a/F1-nolib/chronometer/lidar.h b/F1-nolib/chronometer/lidar.h
index 80c15d3..ad90268 100644
--- a/F1-nolib/chronometer/lidar.h
+++ b/F1-nolib/chronometer/lidar.h
@@ -27,6 +27,9 @@
 #define LIDAR_LOWER_STREN   (10)
 // triggered distance threshold - 1 meter
 #define LIDAR_DIST_THRES    (100)
+#define LIDAR_MIN_DIST      (50)
+#define LIDAR_MAX_DIST      (1000)
+
 extern uint16_t last_lidar_dist;
 extern uint16_t lidar_triggered_dist;
 extern uint16_t last_lidar_stren;
diff --git a/F1-nolib/chronometer/main.c b/F1-nolib/chronometer/main.c
index 6e0e2e2..164e02b 100644
--- a/F1-nolib/chronometer/main.c
+++ b/F1-nolib/chronometer/main.c
@@ -21,6 +21,7 @@
 
 //#include "adc.h"
 #include "GPS.h"
+#include "flash.h"
 #include "hardware.h"
 #include "lidar.h"
 #include "str.h"
@@ -33,11 +34,13 @@
 #define VERSION "0.0.0"
 #endif
 
+// global pseudo-milliseconds counter
 volatile uint32_t Tms = 0;
 
 /* Called when systick fires */
 void sys_tick_handler(void){
     ++Tms;
+    increment_timer();
 }
 
 void iwdg_setup(){
@@ -65,8 +68,8 @@ void iwdg_setup(){
 
 #ifdef EBUG
 char *parse_cmd(char *buf){
+    int32_t N;
     static char btns[] = "BTN0=0, BTN1=0, PPS=0\n";
-    if(buf[1] != '\n') return buf;
     switch(*buf){
         case '0':
             LED_off();
@@ -80,6 +83,16 @@ char *parse_cmd(char *buf){
             btns[20] = GET_PPS() + '0';
             return btns;
         break;
+        case 'C':
+            if(getnum(&buf[1], &N)){
+                SEND("Need a number!\n");
+            }else{
+                addNrecs(N);
+            }
+        break;
+        case 'd':
+            dump_userconf();
+        break;
         case 'p':
             pin_toggle(USBPU_port, USBPU_pin);
             SEND("USB pullup is ");
@@ -117,10 +130,13 @@ char *parse_cmd(char *buf){
             while(1){nop();};
         break;
         default: // help
+            if(buf[1] != '\n') return buf;
             return
             "0/1 - turn on/off LED1\n"
             "'b' - get buttons's state\n"
+            "'d' - dump current user conf\n"
             "'p' - toggle USB pullup\n"
+            "'C' - store userconf for N times\n"
             "'G' - get last LIDAR distance\n"
             "'L' - send long string over USB\n"
             "'R' - software reset\n"
@@ -155,22 +171,55 @@ static char *get_USB(){
     return NULL;
 }
 
-#define CMP(a,b)  cmpstr(a, b, sizeof(b)-1)
 static void parse_USBCMD(char *cmd){
+#define CMP(a,b)  cmpstr(a, b, sizeof(b)-1)
+#define GETNUM(x) if(getnum(cmd+sizeof(x)-1, &N)) goto bad_number;
+    static uint8_t conf_modified = 0;
+    uint8_t succeed = 0;
+    int32_t N;
     if(!cmd || !*cmd) return;
     if(*cmd == '?'){ // help
         USB_send("Commands:\n"
-                 CMD_DISTMIN " - min distance threshold (cm)\n"
-                 CMD_DISTMAX " - max distance threshold (cm)\n"
+                 CMD_DISTMIN   " - min distance threshold (cm)\n"
+                 CMD_DISTMAX   " - max distance threshold (cm)\n"
                  CMD_PRINTTIME " - print time\n"
+                 CMD_STORECONF " - store new configuration in flash\n"
                  );
     }else if(CMP(cmd, CMD_PRINTTIME) == 0){
         USB_send(get_time(&current_time, get_millis()));
     }else if(CMP(cmd, CMD_DISTMIN) == 0){ // set low limit
         DBG("CMD_DISTMIN");
+        GETNUM(CMD_DISTMIN);
+        if(N < 0 || N > 0xffff) goto bad_number;
+        if(the_conf.dist_min != (uint16_t)N){
+            conf_modified = 1;
+            the_conf.dist_min = (uint16_t) N;
+            succeed = 1;
+        }
     }else if(CMP(cmd, CMD_DISTMAX) == 0){ // set low limit
         DBG("CMD_DISTMAX");
+        GETNUM(CMD_DISTMAX);
+        if(N < 0 || N > 0xffff) goto bad_number;
+        if(the_conf.dist_max != (uint16_t)N){
+            conf_modified = 1;
+            the_conf.dist_max = (uint16_t) N;
+            succeed = 1;
+        }
+    }else if(CMP(cmd, CMD_STORECONF) == 0){ // store everything
+        DBG("Store");
+        if(conf_modified){
+            if(store_userconf()){
+                USB_send("Error: can't save data!\n");
+            }else{
+                conf_modified = 0;
+                succeed = 1;
+            }
+        }
     }
+    if(succeed) USB_send("Success!\n");
+    return;
+  bad_number:
+    USB_send("Error: bad number!\n");
 }
 
 int main(void){
@@ -178,9 +227,10 @@ int main(void){
     sysreset();
     StartHSE();
     hw_setup();
+    LED1_off();
     USBPU_OFF();
     usarts_setup();
-    SysTick_Config(72000);
+    SysTick_Config(SYSTICK_DEFLOAD);
     SEND("Chronometer version " VERSION ".\n");
     if(RCC->CSR & RCC_CSR_IWDGRSTF){ // watchdog reset occured
         SEND("WDGRESET=1\n");
@@ -191,14 +241,27 @@ int main(void){
     RCC->CSR |= RCC_CSR_RMVF; // remove reset flags
 
     USB_setup();
-    //iwdg_setup();
+    iwdg_setup();
     USBPU_ON();
+    // read data stored in flash
+#ifdef EBUG
+    SEND("Old config:\n");
+    dump_userconf();
+#endif
+    //writeatend();
+    get_userconf();
+#ifdef EBUG
+    SEND("New config:\n");
+    dump_userconf();
+#endif
 
     while (1){
         IWDG->KR = IWDG_REFRESH; // refresh watchdog
         if(lastT > Tms || Tms - lastT > 499){
             if(need2startseq) GPS_send_start_seq();
             LED_blink();
+            if(GPS_status != GPS_VALID) LED1_blink();
+            else LED1_on();
             lastT = Tms;
             if(usartrx(LIDAR_USART)){
                 char *txt;
@@ -207,7 +270,7 @@ int main(void){
                     DBG(txt);
                 }
             }
-#ifdef EBUG
+#if defined EBUG || defined USART1PROXY
             transmit_tbuf(1); // non-blocking transmission of data from UART buffer every 0.5s
 #endif
             transmit_tbuf(GPS_USART);
@@ -215,23 +278,28 @@ int main(void){
         }
         usb_proc();
         int r = 0;
-        char *txt, *ans;
+        char *txt;
         if((txt = get_USB())){
             parse_USBCMD(txt);
             DBG("Received data over USB:");
             DBG(txt);
             USB_send(txt); // echo all back
         }
-#ifdef EBUG
+#if defined EBUG || defined USART1PROXY
         if(usartrx(1)){ // usart1 received data, store in in buffer
             r = usart_getline(1, &txt);
             if(r){
                 txt[r] = 0;
-                ans = parse_cmd(txt);
+#ifdef EBUG
+                char *ans = parse_cmd(txt);
                 if(ans){
+                    transmit_tbuf(1);
                     usart_send(1, ans);
                     transmit_tbuf(1);
                 }
+#else // USART1PROXY - send received data to GPS
+                usart_send(GPS_USART, txt);
+#endif
             }
         }
 #endif
@@ -251,4 +319,3 @@ int main(void){
     }
     return 0;
 }
-
diff --git a/F1-nolib/chronometer/time.c b/F1-nolib/chronometer/time.c
index c430e6f..6f8f0c3 100644
--- a/F1-nolib/chronometer/time.c
+++ b/F1-nolib/chronometer/time.c
@@ -21,9 +21,13 @@
 #include "usb.h"
 #include <string.h>
 
+volatile uint32_t Timer; // milliseconds counter
 curtime current_time = TMNOTINI;
 volatile int need_sync = 1;
 
+// SysTick->LOAD values for all milliseconds (RVR0) and last millisecond (RVR1)
+static uint32_t RVR0 = SYSTICK_DEFLOAD, RVR1 = SYSTICK_DEFLOAD;
+
 static inline uint8_t atou(const char *b){
     return (b[0]-'0')*10 + b[1]-'0';
 }
@@ -36,6 +40,22 @@ void set_time(const char *buf){
     current_time.S = atou(&buf[4]);
 }
 
+/**
+ * @brief time_increment - increment system timer by systick
+ */
+void time_increment(){
+    Timer = 0;
+    if(current_time.H == 25) return; // Time not initialized
+    if(++current_time.S == 60){
+        current_time.S = 0;
+        if(++current_time.M == 60){
+            current_time.M = 0;
+            if(++current_time.H == 24)
+                current_time.H = 0;
+        }
+    }
+}
+
 /**
  * print time: Tm - time structure, T - milliseconds
  */
@@ -90,3 +110,54 @@ uint32_t get_millis(){
     // TODO: calculate right millis
     return Tms % 1000; // temporary gag
 }
+
+void systick_correction(){
+    uint32_t t = 0, ticks;
+    static uint32_t ticksavr = 0, N = 0, last_corr_time = 0;
+    // correct
+    int32_t systick_val = SysTick->VAL;
+    // SysTick->LOAD values for all milliseconds (RVR0) and last millisecond (RVR1)
+    SysTick->VAL = RVR0;
+    int32_t timer_val = Timer;
+    Timer = 0;
+    // RVR -> SysTick->LOAD
+    systick_val = SysTick->LOAD + 1 - systick_val; // Systick counts down!
+    if(timer_val < 10) timer_val += 1000; // our closks go faster than real
+    else if(timer_val < 990){ // something wrong
+        RVR0 = RVR1 = SYSTICK_DEFLOAD;
+        SysTick->LOAD = RVR0;
+        need_sync = 1;
+        goto theend;
+    }else
+        time_increment(); // ms counter less than 1000 - we need to increment time
+    t = current_time.H * 3600 + current_time.M * 60 + current_time.S;
+    if(t - last_corr_time == 1){ // PPS interval == 1s
+        ticks = systick_val + (timer_val-1)*(RVR0 + 1) + RVR1 + 1;
+        ++N;
+        ticksavr += ticks;
+        if(N > 20){
+            ticks = ticksavr / N;
+            RVR0 = ticks / 1000 - 1; // main RVR value
+            SysTick->LOAD = RVR0;
+            RVR1 = RVR0 + ticks % 1000; // last millisecond RVR value (with fine correction)
+            N = 0;
+            ticksavr = 0;
+            need_sync = 0;
+        }
+    }else{
+        N = 0;
+        ticksavr = 0;
+    }
+theend:
+    last_corr_time = t;
+}
+
+void increment_timer(){
+    ++Timer;
+    if(Timer == 999){
+        SysTick->LOAD = RVR1;
+    }else if(Timer == 1000){
+        SysTick->LOAD = RVR0;
+        time_increment();
+    }
+}
diff --git a/F1-nolib/chronometer/time.h b/F1-nolib/chronometer/time.h
index e8e61cc..d4f8f6c 100644
--- a/F1-nolib/chronometer/time.h
+++ b/F1-nolib/chronometer/time.h
@@ -21,8 +21,11 @@
 
 #include <stm32f1.h>
 
-#define STK_RVR_DEFAULT_VAL  (8999)
-#define TIMEZONE_GMT_PLUS    (3)
+// default value for systick_config
+#define SYSTICK_DEFCONF         (72000)
+// defaul for systick->load
+#define SYSTICK_DEFLOAD         (SYSTICK_DEFCONF - 1)
+#define TIMEZONE_GMT_PLUS       (3)
 
 #define DIDNT_TRIGGERED (2000)
 
@@ -38,6 +41,7 @@ typedef struct{
 } curtime;
 
 extern volatile uint32_t Tms;
+extern volatile uint32_t Timer;
 extern curtime current_time;
 
 extern curtime trigger_time[];
@@ -48,5 +52,8 @@ extern volatile int need_sync;
 char *get_time(curtime *T, uint32_t m);
 void set_time(const char *buf);
 uint32_t get_millis(); // current milliseconds
+void time_increment();
+void systick_correction();
+void increment_timer();
 
 #endif // TIME_H__
diff --git a/F1-nolib/chronometer/usart.c b/F1-nolib/chronometer/usart.c
index 91879f5..6a66524 100644
--- a/F1-nolib/chronometer/usart.c
+++ b/F1-nolib/chronometer/usart.c
@@ -94,7 +94,7 @@ void usart_send(int n, const char *str){
         tbuf[n][tbufno[n]][odatalen[n][tbufno[n]]++] = *str++;
     }
 }
-#ifdef EBUG
+#if defined EBUG || defined USART1PROXY
 // only for USART1
 void newline(){
     usart_putchar(1, '\n');
@@ -168,8 +168,8 @@ static void usart_setup(int n, uint32_t BRR){
 
 void usarts_setup(){
     RCC->AHBENR |= RCC_AHBENR_DMA1EN;
-#ifdef EBUG
-    usart_setup(1, 72000000 / 115200); // debug console
+#if defined EBUG || defined USART1PROXY
+    usart_setup(1, 72000000 / 115200); // debug console or GPS proxy
 #endif
     usart_setup(2, 36000000 / 9600); // GPS
     usart_setup(3, 36000000 / 115200); // LIDAR
@@ -215,7 +215,7 @@ void usart_isr(int n, USART_TypeDef *USART){
     }
 }
 
-#ifdef EBUG
+#if defined EBUG || defined USART1PROXY
 void usart1_isr(){
     usart_isr(1, USART1);
 }
@@ -310,7 +310,7 @@ void hexdump(uint8_t *arr, uint16_t len){
 }
 #endif
 
-#ifdef EBUG
+#if defined EBUG || defined USART1PROXY
 void dma1_channel4_isr(){ // USART1
     if(DMA1->ISR & DMA_ISR_TCIF4){ // Tx
         DMA1->IFCR = DMA_IFCR_CTCIF4; // clear TC flag
@@ -332,3 +332,34 @@ void dma1_channel2_isr(){ // USART3
         txrdy[3] = 1;
     }
 }
+
+// read `buf` and get first integer `N` in it
+// @return 0 if all OK or 1 if there's not a number; omit spaces and '='
+int getnum(const char *buf, int32_t *N){
+    char c;
+    int positive = -1;
+    int32_t val = 0;
+    while((c = *buf++)){
+        if(c == '\t' || c == ' ' || c == '='){
+            if(positive < 0) continue; // beginning spaces
+            else break; // spaces after number
+        }
+        if(c == '-'){
+            if(positive < 0){
+                positive = 0;
+                continue;
+            }else break; // there already was `-` or number
+        }
+        if(c < '0' || c > '9') break;
+        if(positive < 0) positive = 1;
+        val = val * 10 + (int32_t)(c - '0');
+    }
+    if(positive != -1){
+        if(positive == 0){
+            if(val == 0) return 1; // single '-'
+            val = -val;
+        }
+        *N = val;
+    }else return 1;
+    return 0;
+}
diff --git a/F1-nolib/chronometer/usart.h b/F1-nolib/chronometer/usart.h
index d92b605..4ddcf80 100644
--- a/F1-nolib/chronometer/usart.h
+++ b/F1-nolib/chronometer/usart.h
@@ -55,13 +55,13 @@ void usart_putchar(int n, char ch);
 char *u2str(uint32_t val);
 void printu(int n, uint32_t val);
 void printuhex(int n, uint32_t val);
+int getnum(const char *buf, int32_t *N);
 
-#ifdef EBUG
+#if defined EBUG || defined USART1PROXY
 void newline();
+#endif
+#ifdef EBUG
 void hexdump(uint8_t *arr, uint16_t len);
 #endif
-/*
-void hexdump16(uint16_t *arr, uint16_t len);
-void hexdump32(uint32_t *arr, uint16_t len);
-*/
+
 #endif // __USART_H__
diff --git a/F1-nolib/chronometer/usb.c b/F1-nolib/chronometer/usb.c
index 4fc2fa8..f9ad6db 100644
--- a/F1-nolib/chronometer/usb.c
+++ b/F1-nolib/chronometer/usb.c
@@ -102,6 +102,10 @@ void usb_proc(){
 }
 
 void USB_send(char *buf){
+    if(!USB_configured()){
+        DBG("USB not configured");
+        return;
+    }
     uint16_t l = 0, ctr = 0;
     char *p = buf;
     while(*p++) ++l;
diff --git a/F1-nolib/inc/ld/stm32f01234.ld b/F1-nolib/inc/ld/stm32f01234.ld
index 76abafe..930bf36 100644
--- a/F1-nolib/inc/ld/stm32f01234.ld
+++ b/F1-nolib/inc/ld/stm32f01234.ld
@@ -52,7 +52,7 @@ SECTIONS {
     . = ALIGN(4);
     _etext = .;
   } >rom
-  
+
   .ARM.extab :
   {
     *(.ARM.extab* .gnu.linkonce.armextab.*)
@@ -71,6 +71,12 @@ SECTIONS {
     _edata = .;
   } >ram AT >rom
 
+  .myvars :
+  {
+    . = ALIGN(1024);
+    KEEP(*(.myvars))
+  } > rom
+
   _ldata = LOADADDR(.data);
 
   .bss :
@@ -84,4 +90,4 @@ SECTIONS {
   } >ram
 }
 
-PROVIDE(_stack = ORIGIN(ram) + LENGTH(ram));
\ No newline at end of file
+PROVIDE(_stack = ORIGIN(ram) + LENGTH(ram));