3 ![jj40](https://ae01.alicdn.com/kf/HTB18bq6bOERMeJjSspiq6zZLFXar.jpg?size=359506&height=562&width=750&hash=663a22d0109e2416ec8f54a7658686da)
5 A compact 40% (12x4) ortholinear keyboard kit made and KPRepublic on AliExpress.
7 Keyboard Maintainer: [QMK Community](https://github.com/qmk)
8 Hardware Supported: Atmega32A
9 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)
11 Make example for this keyboard (after setting up your build environment):
13 make jj40:default:program
15 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.
17 Note that this is a complete replacement for the firmware, so you won't be
18 using Bootmapper Client to change any keyboard settings, since not all the
19 USB report options are supported.
21 In addition you may need the AVR toolchain and `bootloadHID` for flashing:
24 $ brew cask install crosspack-avr
25 $ brew install --HEAD https://raw.githubusercontent.com/robertgzr/homebrew-tap/master/bootloadhid.rb
28 In order to use the `./program` script, which can reboot the board into
29 the bootloader, you'll need Python 2 with PyUSB installed:
35 If you prefer, you can just build it and flash the firmware directly with
36 `bootloadHID` if you boot the board while holding down `Backspace` (`Top Right Key`) to keep it
41 $ bootloadHID -r jj40_default.hex
46 1. Try plugging the board in while pressing `Backspace` (`Top Right Key`). This will force it
47 to boot only the bootloader without loading the firmware. Once this is
48 done, just reflash the board with the original firmware.
49 2. Sometimes USB hubs can act weird, so try connecting the board directly
50 to your computer or plugging/unplugging the USB hub.
51 3. If you get an error such as "Resource Unavailable" when attemting to flash
52 on Linux, you may want to compile and run `tools/usb_detach.c`. See `tools/README.md`