diff --git a/G0:G070/i2c/Makefile b/G0:G070/i2c/Makefile
index 364a3a4..7c5a85f 100644
--- a/G0:G070/i2c/Makefile
+++ b/G0:G070/i2c/Makefile
@@ -64,12 +64,11 @@ CFLAGS		+= -O2 -MD -D__thumb2__=1
 CFLAGS		+= -Wall -Werror -Wextra -Wshadow -Wimplicit-function-declaration
 CFLAGS		+= -Wredundant-decls $(INCLUDE)
 # -Wmissing-prototypes -Wstrict-prototypes
-CFLAGS		+= -fno-common -ffunction-sections -fdata-sections
+CFLAGS		+= -fno-common -ffunction-sections -fdata-sections 
 
 ###############################################################################
 # Linker flags
-LDFLAGS		+= --static -nostartfiles
-#--specs=nano.specs
+LDFLAGS		+= --static -nostartfiles --specs=nano.specs 
 LDFLAGS		+= -L$(LIB_DIR)
 LDFLAGS		+= -T$(LDSCRIPT)
 LDFLAGS		+= -Wl,-Map=$(OBJDIR)/$(BINARY).map
@@ -146,7 +145,7 @@ clean:
 	@rmdir $(OBJDIR) 2>/dev/null || true
 
 size: $(ELF)
-	$(SIZE) $(ELF)
+	$(SIZE) -Ax $(ELF)
 
 flash: $(BIN)
 	@echo "  FLASH  $(BIN)"
diff --git a/G0:G070/i2c/i2c.c b/G0:G070/i2c/i2c.c
index 63bf7df..f8b62ab 100644
--- a/G0:G070/i2c/i2c.c
+++ b/G0:G070/i2c/i2c.c
@@ -59,6 +59,8 @@ void i2c_setup(I2C_SPEED speed){
             6 << (6 * 4) | 6 << (7 * 4);
     GPIOB->MODER = (GPIOB->MODER & ~(GPIO_MODER_MODE6 | GPIO_MODER_MODE7)) |
                     GPIO_MODER_MODER6_AF | GPIO_MODER_MODER7_AF;
+    GPIOB->PUPDR = (GPIOB->PUPDR & !(GPIO_PUPDR_PUPD6 | GPIO_PUPDR_PUPD7)) |
+            GPIO_PUPDR6_PU | GPIO_PUPDR7_PU; // pullup
     GPIOB->OTYPER |= GPIO_OTYPER_OT6 | GPIO_OTYPER_OT7; // both open-drain outputs
     // I2C (default timing from PCLK - 64MHz)
     RCC->APBENR1 |= RCC_APBENR1_I2C1EN; // clocking
@@ -142,7 +144,7 @@ static uint8_t write_i2cs(uint8_t addr, uint8_t *data, uint8_t nbytes, uint8_t s
                 return 0;
             }
             if(Tms - cntr > I2C_TIMEOUT){
-                USND("Timeout\n");
+                //USND("Timeout\n");
                 return 0;
             }
         }
@@ -198,11 +200,11 @@ static uint8_t read_i2cb(uint8_t addr, uint8_t *data, uint8_t nbytes, uint8_t bu
             IWDG->KR = IWDG_REFRESH;
             if(I2C1->ISR & I2C_ISR_NACKF){
                 I2C1->ICR |= I2C_ICR_NACKCF;
-                USND("NAK\n");
+                //USND("NAK\n");
                 return 0;
             }
             if(Tms - cntr > I2C_TIMEOUT){
-                USND("Timeout\n");
+                //USND("Timeout\n");
                 return 0;
             }
         }
@@ -261,7 +263,8 @@ int i2c_scan_next_addr(uint8_t *addr){
     /*while(!u3txrdy);
     USND("Addr: "); USND(uhex2str(i2caddr)); USND("\n");
     usart3_sendbuf();*/
-    if(!read_i2c_reg((i2caddr++)<<1, 0, NULL, 0)) return 0;
+    uint8_t byte;
+    if(!read_i2c((i2caddr++)<<1, &byte, 1)) return 0;
     return 1;
 }
 
diff --git a/G0:G070/i2c/i2cscan.bin b/G0:G070/i2c/i2cscan.bin
index a974399..7c289ce 100755
Binary files a/G0:G070/i2c/i2cscan.bin and b/G0:G070/i2c/i2cscan.bin differ
diff --git a/G0:G070/i2c/usart.c b/G0:G070/i2c/usart.c
index f3c6186..a420719 100644
--- a/G0:G070/i2c/usart.c
+++ b/G0:G070/i2c/usart.c
@@ -27,17 +27,17 @@
 #define DMATXCCR    (DMA_CCR_MINC | DMA_CCR_DIR | DMA_CCR_TCIE | DMA_CCR_TEIE)
 
 volatile int u3txrdy = 1, u3rxrdy = 0; // transmission done, next line received
-static int bufovr = 0, wasbufovr = 0; // Rx buffer overflow or error flag -> delete next line
-static int rbufno = 0, tbufno = 0; // current buf number
-static char rbuf[2][UARTBUFSZ], tbuf[2][UARTBUFSZ]; // receive & transmit buffers
-static int rxlen[2] = {0}, txlen[2] = {0};
+static volatile int bufovr = 0, wasbufovr = 0; // Rx buffer overflow or error flag -> delete next line
+static volatile int rbufno = 0, tbufno = 0; // current buf number
+static volatile char rbuf[2][UARTBUFSZ], tbuf[2][UARTBUFSZ]; // receive & transmit buffers
+static volatile int rxlen[2] = {0}, txlen[2] = {0};
 
 char *usart3_getline(int *wasbo){
     if(wasbo) *wasbo = wasbufovr;
     wasbufovr = 0;
     if(!u3rxrdy) return NULL;
     u3rxrdy = 0; // clear ready flag
-    return rbuf[!rbufno]; // current buffer is in filling stage, return old - filled - buffer
+    return (char*)rbuf[!rbufno]; // current buffer is in filling stage, return old - filled - buffer
 }
 
 #define USART_BRR(speed)    ((64000000 + speed/2) / speed)
@@ -84,7 +84,7 @@ int usart3_send(const char *str, int len){
     int rest = UARTBUFSZ - txlen[tbufno];
     if(rest == 0 && !u3txrdy) return 0; // buffer is full while transmission in process
     if(len < rest) rest = len;
-    mymemcpy(tbuf[tbufno] + txlen[tbufno], str, rest);
+    mymemcpy((char*)(tbuf[tbufno] + txlen[tbufno]), str, rest);
     txlen[tbufno] += rest;
     if(!u3txrdy) return rest;
     if(txlen[tbufno] == UARTBUFSZ) usart3_sendbuf();
@@ -92,7 +92,7 @@ int usart3_send(const char *str, int len){
     len -= rest;
     // now fill another - empty - buffer
     if(len > UARTBUFSZ) len = UARTBUFSZ;
-    mymemcpy(tbuf[tbufno], str + rest, len);
+    mymemcpy((char*)tbuf[tbufno], str + rest, len);
     txlen[tbufno] = len;
     return rest + len;
 }
@@ -157,7 +157,6 @@ void dma1_channel2_3_isr(){
     uint32_t isr = DMA1->ISR;
     if(isr & (DMA_ISR_TCIF2 | DMA_ISR_TEIF2)){ // transfer complete or error
         u3txrdy = 1;
-        //DMA1_Channel2->CCR = DMATXCCR;
     }
     if(isr & (DMA_ISR_TCIF3 | DMA_ISR_TEIF3)){ // receive complete or error -> buffer overflow
         if(rbuf[rbufno][UARTBUFSZ-1] != '\n'){ // last symbol is not a newline