user-1: Unable to flash Arduino when TXD pin of HC-6 Bluetooth module is connected to Arduino RXD pin?
I get the following error:

Flashing with command:C:/Users/home/.arduino-create/arduino/avrdude/6.3.0-arduino9/bin/avrdude.exe -CC:/Users/home/.arduino-create/arduino/avrdude/6.3.0-arduino9/etc/avrdude.conf -q -q -patmega328p -carduino -PCOM4 -b57600 -D -Uflash:w:C:/Users/home/AppData/Local/Temp/arduino-create-agent051272951/sketch_jun10a.hex:i
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x48


user-1: Most* Arduino devices are flashed through a bootloader which communicates over the serial pins. If you've connected another device to those pins, that communication may fail. You may need to disconnect the device while you flash the Arduino.
(*: The exceptions are the 32u4-based devices, like the Leonardo and Micro. These communicate directly over USB.)

-1: <p>Unable to flash Arduino when TXD pin of HC-6 Bluetooth module is connected to Arduino RXD pin?</p>
<p>I get the following error:</p>
<blockquote>
<p>Flashing with command:C:/Users/home/.arduino-create/arduino/avrdude/6.3.0-arduino9/bin/avrdude.exe -CC:/Users/home/.arduino-create/arduino/avrdude/6.3.0-arduino9/etc/avrdude.conf -q -q -patmega328p -carduino -PCOM4 -b57600 -D -Uflash:w:C:/Users/home/AppData/Local/Temp/arduino-create-agent051272951/sketch_jun10a.hex:i</p>
<p>avrdude: stk500_recv(): programmer is not responding</p>
<p>avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x48</p>
</blockquote>
 -1: <p>Most* Arduino devices are flashed through a bootloader which communicates over the serial pins. If you've connected another device to those pins, that communication may fail. You may need to disconnect the device while you flash the Arduino.</p>

<p>(*: The exceptions are the 32u4-based devices, like the Leonardo and Micro. These communicate directly over USB.)</p>
