How to flash custom firmware to the PCB
Programming the firmware (Windows):
1. Download and install FLIP (http://www.atmel.com/tools/FLIP.aspx)
2. Connect the keyboard and press the reset button
3. Open device manager, find the ATMEGA32u4 chip and click "update driver"
4. Choose location manually: folder named "USB" inside the installation directory of FLIP
5. Once the driver is installed, open FLIP
6. Device -> Select: choose ATMEGA32u4
7. Settings -> Communication -> USB, FLIP should show the signature at this point (58 1E 95 87)
8. File -> Load HEX file: select the hex file you created using qmk.sized.io
9. click "Run"
10. After programming is done, disconnect the device from USB and connect again.
Programming the firmware (Linux):
1. Download and install/compile/unpack dfu-programmer from http://dfu-programmer.sourceforge.net/.
2. Issue the following commands in the command prompt after connecting the device and pressing the programming button (S1). You may need root permissions or udev rules to do that.
sudo dfu-programmer atmega32u4 erase
sudo dfu-programmer atmega32u4 flash [name of hex file]
sudo dfu-programmer atmega32u4 start
The keyboard should start working. If it doesn't, reconnect the cable."