A alternative PCB for Viper and Eagle V2 and V3
Make example for this keyboard (after setting up your build environment):
make 4pplet/eagle_viper_rep/rev_b:default
See the build environment setup and the make instructions for more information. Brand new to QMK? Start with our Complete Newbs Guide.
How to enter bootloader (DFU):
Press and hold the button on the keyboard (the small one on the same side as the MCU) for more than 1 second. The keyboard will then enter bootloader (DFU) mode and it's ready to flash the firmware.
Note: If holding the button a shorter time, the keyboard will just reset. If you want to exit bootloader mode without flashing a firmware, dissconnect the keyboard from your PC and reconnect it.
Alternative option if the firmware is already pre-flashed: