diff --git a/F1-nolib/CDC_ACM/Makefile b/F1-nolib/CDC_ACM/Makefile
index 66de9fb..a9b2514 100644
--- a/F1-nolib/CDC_ACM/Makefile
+++ b/F1-nolib/CDC_ACM/Makefile
@@ -1,3 +1,5 @@
+# make debug adds -DEBUG -Werror
+# make ADDEFS="additional defs"
 BINARY		= cdcacm
 BOOTPORT	?= /dev/ttyUSB0
 BOOTSPEED	?= 115200
@@ -9,10 +11,10 @@ MCU			?= F103x8
 DENSITY 	?= MD
 # change this linking script depending on particular MCU model,
 LDSCRIPT	?= stm32f103x8.ld
-# debug
-#DEFS		= -DEBUG
-
-INDEPENDENT_HEADERS=
+DEFS		= ${ADDEFS} -DVERSION=\"0.0.1\"
+TARGET := RELEASE
+# proxy GPS output over USART1
+#DEFS += -DUSART1PROXY
 
 FP_FLAGS	?= -msoft-float -mfloat-abi=soft
 ASM_FLAGS	?= -mthumb -mcpu=cortex-m3 -mfix-cortex-m3-ldrd
@@ -57,13 +59,13 @@ LIB_DIR		:= $(INC_DIR)/ld
 ###############################################################################
 # C flags
 CFLAGS		+= -O2 -g -D__thumb2__=1 -MD
-CFLAGS		+= -Wall -Werror -Wextra -Wshadow 
+CFLAGS		+= -Wall -Wextra -Wshadow 
 CFLAGS		+= -fno-common -ffunction-sections -fdata-sections -fno-stack-protector
 CFLAGS		+=  $(ARCH_FLAGS)
 
 ###############################################################################
 # Linker flags
-LDFLAGS		+= -nostartfiles --static -nostdlibs 
+LDFLAGS		+= --static -nostartfiles -nostdlibs 
 LDFLAGS		+= -L$(LIB_DIR) -L$(TOOLCHLIB)
 LDFLAGS		+= -T$(LDSCRIPT)
 
@@ -71,14 +73,31 @@ LDFLAGS		+= -T$(LDSCRIPT)
 # Used libraries
 LDLIBS		+=  -lc $(shell $(CC) $(CFLAGS) -print-libgcc-file-name)
 
-PLATFRM		?= -DSTM32$(FAMILY) -DSTM32$(MCU) -DSTM32F10X_$(DENSITY)
+DEFS		+= -DSTM32$(FAMILY) -DSTM32$(MCU) -DSTM32F10X_$(DENSITY)
 
 ELF		:= $(OBJDIR)/$(BINARY).elf
 LIST	:= $(OBJDIR)/$(BINARY).list
 BIN		:= $(BINARY).bin
 HEX		:= $(BINARY).hex
 
-all: bin list size
+all: $(OBJDIR)/RELEASE bin list size
+release: all
+
+debug: CFLAGS += -DEBUG -Werror
+debug: $(OBJDIR)/DEBUG bin list size
+
+$(OBJDIR)/DEBUG: 
+	@rm -rf $(OBJDIR)
+	@mkdir $(OBJDIR)
+	@> $(OBJDIR)/DEBUG
+	@echo "TARGET: DEBUG"
+	echo "CFLAGS += -DEBUG -Werror" > $(OBJDIR)/CFLAGS
+$(OBJDIR)/RELEASE:
+	@rm -rf $(OBJDIR)
+	@mkdir $(OBJDIR)
+	@> $(OBJDIR)/RELEASE
+	@echo "TARGET: RELEASE"
+	echo "" > $(OBJDIR)/CFLAGS
 
 elf: $(ELF)
 bin: $(BIN)
@@ -87,17 +106,18 @@ list: $(LIST)
 
 ifneq ($(MAKECMDGOALS),clean)
 -include $(DEPS)
+-include $(OBJDIR)/CFLAGS
 endif
 
 $(OBJDIR):
 	mkdir $(OBJDIR)
 
 $(STARTUP): $(INC_DIR)/startup/vector.c
-	$(CC) $(CFLAGS) $(DEFS) $(PLATFRM) $(INCLUDE) -o $@ -c $<
+	$(CC) $(CFLAGS) $(DEFS) $(INCLUDE) -o $@ -c $<
 
 $(OBJDIR)/%.o: %.c
 	@echo "  CC      $<"
-	$(CC) $(CFLAGS) $(DEFS) $(PLATFRM) $(INCLUDE) -o $@ -c $<
+	$(CC) $(CFLAGS) $(DEFS) $(INCLUDE) -o $@ -c $<
 
 $(BIN): $(ELF)
 	@echo "  OBJCOPY $(BIN)"
@@ -111,7 +131,7 @@ $(LIST): $(ELF)
 	@echo "  OBJDUMP $(LIST)"
 	$(OBJDUMP) -S $(ELF) > $(LIST)
 
-$(ELF): $(OBJDIR) $(OBJS)
+$(ELF): $(OBJDIR) $(OBJS) 
 	@echo "  LD      $(ELF)"
 	$(LD) $(LDFLAGS) $(OBJS) $(LDLIBS) -o $(ELF)
 
@@ -120,13 +140,13 @@ size: $(ELF)
 
 clean:
 	@echo "  CLEAN"
-	$(RM) $(OBJS) $(DEPS) $(ELF) $(HEX) $(LIST)
-	@rmdir $(OBJDIR) 2>/dev/null || true
+	@$(RM) $(HEX)
+	@$(RM) -rf $(OBJDIR) 2>/dev/null || true
 
 
 flash: $(BIN)
 	@echo "  FLASH  $(BIN)"
-	$(STFLASH) write $(BIN) 0x8000000
+	$(STFLASH) --reset write $(BIN) 0x8000000
 
 boot: $(BIN)
 	@echo "  LOAD $(BIN) through bootloader"
diff --git a/F1-nolib/CDC_ACM/main.c b/F1-nolib/CDC_ACM/main.c
index c5fbdcd..f754a47 100644
--- a/F1-nolib/CDC_ACM/main.c
+++ b/F1-nolib/CDC_ACM/main.c
@@ -129,6 +129,21 @@ void break_handler(){
     br = 1;
 }
 
+char *u2str(uint32_t val){
+    static char strbuf[11];
+    char *bufptr = &strbuf[10];
+    *bufptr = 0;
+    if(!val){
+        *(--bufptr) = '0';
+    }else{
+        while(val){
+            *(--bufptr) = val % 10 + '0';
+            val /= 10;
+        }
+    }
+    return bufptr;
+}
+
 int main(void){
     uint32_t lastT = 0, Tp = 499;
     sysreset();
@@ -150,15 +165,22 @@ int main(void){
     iwdg_setup();
     USBPU_ON();
 
+    uint32_t ctr = 0;
     while (1){
         IWDG->KR = IWDG_REFRESH; // refresh watchdog
         if(lastT > Tms || Tms - lastT > Tp){
             LED_blink(LED0);
             lastT = Tms;
-            USB_send("Hello!\n");
+            if(usbON){
+                USB_send("String #");
+                char *s = u2str(ctr++);
+                //SEND(s); SEND("th string"); newline();
+                USB_send(s);
+                USB_send("\n");
+            }
         }
         usb_proc();
-        if(USB_connected()) Tp = 999;
+        if(usbON) Tp = 999;
         else Tp = 499;
         char *txt, *ans;
         if((txt = get_USB())){
diff --git a/F1-nolib/CDC_ACM/usart.h b/F1-nolib/CDC_ACM/usart.h
index a4442f0..f49217a 100644
--- a/F1-nolib/CDC_ACM/usart.h
+++ b/F1-nolib/CDC_ACM/usart.h
@@ -36,6 +36,7 @@
 
 #ifdef EBUG
 #define DBG(str)  do{SEND(__func__); SEND(": " str); newline();}while(0)
+#define MSG(str)    do{SEND(str); newline();}while(0)
 #else
 #define MSG(str)
 #define DBG(str)
diff --git a/F1-nolib/CDC_ACM/usb.c b/F1-nolib/CDC_ACM/usb.c
index 34e4859..7b31f77 100644
--- a/F1-nolib/CDC_ACM/usb.c
+++ b/F1-nolib/CDC_ACM/usb.c
@@ -57,12 +57,7 @@ static uint16_t EP23_Handler(ep_t ep){
                 return ep.status;
             }
         }
-        // end of transaction: clear DTOGs
-        //ep.status = CLEAR_DTOG_RX(ep.status);
-        //ep.status = CLEAR_DTOG_TX(ep.status);
-        //ep.status = SET_STALL_TX(ep.status);
     }else if (ep.tx_flag){
-        //ep.status = KEEP_STAT_TX(ep.status);
         tx_succesfull = 1;
     }
     ep.status = SET_VALID_RX(ep.status);
@@ -93,19 +88,24 @@ void usb_proc(){
             EP_Init(2, EP_TYPE_BULK, 0, USB_RXBUFSZ, EP23_Handler); // OUT2 - receive data
             EP_Init(3, EP_TYPE_BULK, USB_TXBUFSZ, 0, EP23_Handler); // IN3 - transmit data
             USB_Dev.USB_Status = USB_STATE_CONNECTED;
+            DBG("Connected");
         break;
         case USB_STATE_DEFAULT:
         case USB_STATE_ADDRESSED:
-            usbON = 0;
+            if(usbON){
+                DBG("def/adr");
+                usbON = 0;
+            }
         default:
             return;
     }
 }
 
 void USB_send(const char *buf){
-    if(!usbON) return;
+    if(!usbON) return; // USB disconnected
     uint16_t l = 0, ctr = 0;
     const char *p = buf;
+    //SEND("buf: "); SEND(buf); newline();
     while(*p++) ++l;
     while(l){
         uint16_t s = (l > USB_TXBUFSZ) ? USB_TXBUFSZ : l;
@@ -115,7 +115,7 @@ void USB_send(const char *buf){
         while(--ctra && tx_succesfull == 0){
             IWDG->KR = IWDG_REFRESH;
         }
-        if(tx_succesfull == 0){usbON = 0; DBG("USB transfer error"); return;} // usb is OFF?
+        if(tx_succesfull == 0){usbON = 0; DBG("USB disconnected"); return;} // usb is OFF?
         l -= s;
         ctr += s;
     }
@@ -128,7 +128,7 @@ void USB_send(const char *buf){
  * @return amount of received bytes
  */
 int USB_receive(char *buf, int bufsize){
-    if(!bufsize || !idatalen) return 0;
+    if(bufsize < 1 || !idatalen) return 0;
     uint32_t oldcntr = USB->CNTR;
     USB->CNTR = 0;
     int sz = (idatalen > bufsize) ? bufsize : idatalen, rest = idatalen - sz;
@@ -149,10 +149,3 @@ int USB_receive(char *buf, int bufsize){
     return sz;
 }
 
-/**
- * @brief USB_configured
- * @return 1 if USB is in configured state
- */
-int USB_connected(){
-    return usbON;
-}
diff --git a/F1-nolib/CDC_ACM/usb.h b/F1-nolib/CDC_ACM/usb.h
index 6940993..a780e5f 100644
--- a/F1-nolib/CDC_ACM/usb.h
+++ b/F1-nolib/CDC_ACM/usb.h
@@ -32,6 +32,5 @@ void USB_setup();
 void usb_proc();
 void USB_send(const char *buf);
 int USB_receive(char *buf, int bufsize);
-int USB_connected();
 
 #endif // __USB_H__
diff --git a/F1-nolib/CDC_ACM/usb_lib.c b/F1-nolib/CDC_ACM/usb_lib.c
index c00c8a0..6ddc547 100644
--- a/F1-nolib/CDC_ACM/usb_lib.c
+++ b/F1-nolib/CDC_ACM/usb_lib.c
@@ -32,6 +32,7 @@ static usb_LineCoding lineCoding = {115200, 0, 0, 8};
 config_pack_t setup_packet;
 static uint8_t ep0databuf[EP0DATABUF_SIZE];
 static uint8_t ep0dbuflen = 0;
+uint8_t USB_connected = 0;
 
 usb_LineCoding getLineCoding(){return lineCoding;}
 
@@ -187,14 +188,17 @@ USB_STRING(USB_StringProdDescriptor, u"USB-Serial Controller");
  */
 // SET_LINE_CODING
 void WEAK linecoding_handler(usb_LineCoding __attribute__((unused)) *lcd){
+    MSG("linecoding_handler()");
 }
 
 // SET_CONTROL_LINE_STATE
 void WEAK clstate_handler(uint16_t __attribute__((unused)) val){
+    MSG("clstate_handler()");
 }
 
 // SEND_BREAK
 void WEAK break_handler(){
+    MSG("break_handler()");
 }
 
 static uint16_t wr0(const uint8_t *buf, uint16_t size, uint16_t status){
@@ -339,12 +343,14 @@ static uint16_t EP0_Handler(ep_t ep){
                         EP_WriteIRQ(0, (uint8_t*)&lineCoding, sizeof(lineCoding));
                     break;
                     case SET_LINE_CODING: // omit this for next stage, when data will come
+                        usbON = 1;
                     break;
                     case SET_CONTROL_LINE_STATE:
                         usbON = 1;
                         clstate_handler(setup_packet.wValue);
                     break;
                     case SEND_BREAK:
+                        usbON = 0;
                         break_handler();
                     break;
                     default:
@@ -431,6 +437,7 @@ int EP_Init(uint8_t number, uint8_t type, uint16_t txsz, uint16_t rxsz, uint16_t
 void usb_lp_can_rx0_isr(){
     if (USB->ISTR & USB_ISTR_RESET){
         usbON = 0;
+        USB_connected = 0;
         // Reinit registers
         USB->CNTR = USB_CNTR_RESETM | USB_CNTR_CTRM | USB_CNTR_SUSPM;
         // Endpoint 0 - CONTROL
diff --git a/F1-nolib/chronometer/main.c b/F1-nolib/chronometer/main.c
index 635e963..e6a6b5c 100644
--- a/F1-nolib/chronometer/main.c
+++ b/F1-nolib/chronometer/main.c
@@ -241,6 +241,7 @@ int main(void){
     // !!! hw_setup() should be the first in setup stage
     hw_setup();
     USB_setup();
+    flashstorage_init();
     USBPU_ON();
     usarts_setup();
 #ifdef EBUG
@@ -254,7 +255,6 @@ int main(void){
 #endif
     RCC->CSR |= RCC_CSR_RMVF; // remove reset flags
     // read data stored in flash
-    flashstorage_init();
     iwdg_setup();
 
     while (1){