keychron_qmk_firmware/keyboards/jj40/README.md

# jj40

![jj40](https://ae01.alicdn.com/kf/HTB18bq6bOERMeJjSspiq6zZLFXar.jpg?size=359506&height=562&width=750&hash=663a22d0109e2416ec8f54a7658686da)

A compact 40% (12x4) ortholinear keyboard kit made and KPRepublic on AliExpress.

Keyboard Maintainer: [QMK Community](https://github.com/qmk)  
Hardware Supported: Atmega32A  
Hardware Availability: [AliExpress](https://www.aliexpress.com/store/product/jj40-Custom-Mechanical-Keyboard-40-PCB-programmed-40-planck-layouts-bface-firmware-gh40/3034003_32828781103.html)

Make example for this keyboard (after setting up your build environment):

    make jj40:default:program

See [build environment setup](https://docs.qmk.fm/build_environment_setup.html) then the [make instructions](https://docs.qmk.fm/make_instructions.html) for more information.

Note that this is a complete replacement for the firmware, so you won't be
using Bootmapper Client to change any keyboard settings, since not all the
USB report options are supported.

In addition you may need the AVR toolchain and `bootloadHID` ([GitHub repo](https://github.com/whiteneon/bootloadHID)) for flashing:

For macOS:
```
$ brew cask install crosspack-avr
$ brew install --HEAD https://raw.githubusercontent.com/robertgzr/homebrew-tap/master/bootloadhid.rb
```

For Linux:
```
$ sudo apt install libusb-dev
$ wget https://www.obdev.at/downloads/vusb/bootloadHID.2012-12-08.tar.gz
$ tar -xzf bootloadHID.2012-12-08.tar.gz
$ cd bootloadHID.2012-12-08/commandline
$ make
$ sudo cp bootloadHID /usr/bin
```

In order to use the `./program` script, which can reboot the board into
the bootloader, you'll need Python 2 with PyUSB installed:

```
$ pip install pyusb
```

If you prefer (or are having issues with a `program` flash), you can just build it (`make jj40:<keymap-name>` and flash the firmware (`.hex` file) directly with
`bootloadHID` if you boot the board while holding down `Backspace` (`Top Right Key`) to keep it
in the bootloader:

```
$ make jj40
$ bootloadHID -r jj40_default.hex
```

## Troubleshooting

1. Try plugging the board in while pressing `Backspace` (`Top Right Key`). This will force it
   to boot only the bootloader without loading the firmware. Once this is
   done, just reflash the board with the original firmware.
2. Sometimes USB hubs can act weird, so try connecting the board directly
   to your computer or plugging/unplugging the USB hub.
3. If you get an error such as "Resource Unavailable" when attemting to flash
   on Linux, you may want to compile and run `tools/usb_detach.c`. See `tools/README.md`
   for more info.