diff --git a/Makefile b/Makefile
index 76a898b..7f25d98 100644
--- a/Makefile
+++ b/Makefile
@@ -22,7 +22,7 @@ MCU=attiny85
 # TARGET_PLATFORM=m328p
 # for attiny85
 TARGET_PLATFORM=t85
-USB_PORT=usb:001:013
+USB_PORT=usb:001:006
 
 LD_FLAGS=-DF_CPU=$(CLOCK_FREQ)
 
diff --git a/src/driver/i2c.c b/src/driver/i2c.c
index 2d77605..3f87e5a 100644
--- a/src/driver/i2c.c
+++ b/src/driver/i2c.c
@@ -56,7 +56,7 @@ bool i2c_start() {
   // ensure both lines are high
   i2c_port |= (_BV(i2c_sda) | _BV(i2c_scl));
   // wait till clock pin is high
-  while (!(i2c_pin & _BV(i2c_scl)));
+  while (!(i2c_port & _BV(i2c_scl)));
   _delay_us(T2_TWI);
 
   // pull data line low
@@ -104,7 +104,7 @@ unsigned char transfer(unsigned char mask) {
     // wait short
     _delay_us(T4_TWI);
     // toggle clock again
-    i2c_control = _BV(USITC);
+    i2c_control |= _BV(USITC);
 
   } while (!(i2c_status & _BV(USIOIF)));
   _delay_us(T2_TWI);