# RS40 A compact 40% keyboard with 42 keys. * Keyboard Maintainer: [Audite Marlow](https://github.com/auditemarlow) * Hardware Supported: RS40 PCB * Hardware Availability: [KJ-Modify Store on AliExpress](https://www.aliexpress.us/item/3256803963501165.html) Make example for this keyboard (after setting up your build environment): make kj_modify/rs40:default Flashing example for this keyboard: make kj_modify/rs40:default:flash See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs). ## Bootloader Enter the bootloader in 3 ways: * **Bootmagic reset**: Hold down the key at (0,0) in the matrix (usually the top left key or Escape) and plug in the keyboard * **Physical reset button**: Briefly press the button on the back of the PCB - some may have pads you must short instead * **Keycode in layout**: Press the key mapped to `QK_BOOT` if it is available