This is what the 10K resistor between RX and ground fixes. Without it the chip is never getting past the bootloader due to noise on the line. Are you sure you had the resistor in place correctly and it was making contact?
I could kiss you right now... Tried again and soldered real "pin connectors" (...) to the resistor. Worked absolutely 100%. Thank you so much 
I will go to sleep now, ashamed, but happy =)