Use Atmel's default bootloader size, rather than Teensy 2.0's [1]. [1] https://github.com/qmk/qmk_firmware/pull/1207#discussion_r109712786
@@ -45,7 +45,7 @@ OPT_DEFS += -DINTERRUPT_CONTROL_ENDPOINT
# Atmel DFU loader 4096
# LUFA bootloader 4096
# USBaspLoader 2048
-OPT_DEFS += -DBOOTLOADER_SIZE=512
+OPT_DEFS += -DBOOTLOADER_SIZE=4096
# Build Options