grbl for Arduino Uno / Nano (Atmega328)
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grbl_v0.9i_Servo.hex	just two Servo positions for Spindle on/off
from https://github.com/robottini/grbl-servo

grbl_v1.1f_Servo.hex	variable Servo position via Spindle speed
https://github.com/cprezzi/grbl-servo

grbl_v1.1f_Servo_switch_dir_step.hex same as before but dir and step pins are switched, to be compatible with cheap nano-cnc-shield.

grbl_v1.1h.20190825.hex	regular grbl version
from https://github.com/gnea/grbl

grbl for coreXY setup
v1.1_GRBL_coreXY_servo___.ino.standard.hex
v1.1_GRBL_coreXY_servo___.ino.with_bootloader.standard.hex
from https://www.electrodragon.com/w/Arduino_CNC#Further_Use.2C_Documentation



grbl for Arduino Mega2560
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grbl-Mega-5X-v1.1l.20190605.hex
from https://github.com/fra589/grbl-Mega-5X

grbl-Mega-5X-v1.1p.20201228_end_stops.hex
compiled with hard-limits by 78Matteo78 