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).
* **Bootmagic reset**: Hold down the top left key and plug in the keyboard. This will also clear EEPROM, so it is a good first step if the keyboard is misbehaving.
* **Physical reset**: Press the 6x6mm button on the underside of the keyboard. On Rev1, it is above the Pro Micro; on Rev2, it is below the OLED.
* **Keycode in layout**: Press the key mapped to `QK_BOOT`. In the pre-supplied keymaps it is on the second layer, replacing the R key.
As a Pro Micro-compatible board, the BDE defines `caterina` as its bootloader by default. Many popular Pro Micro alternatives like the Elite-C, Bit-C, Sea-Micro, Puchi-C etc should be flashed with a different bootloader such as `atmel-dfu`.
**If the incorrect bootloader is specified, bootmagic reset and the `QK_BOOT` keycode will not work**.
To avoid this problem, set the correct bootloader in your custom keymap's `rules.mk` file before compiling, or flash using an appropriate target (e.g. `make mechwild/bde:default:dfu`). See [flashing instructions and bootloader information](https://docs.qmk.fm/#/flashing) for more details.