Hola Leonardo, los archivos del firmware puedes encontrarlos en https://github.com/angellm/grbl
Y las instrucciones para compilarlo y flashearlo en https://github.com/AngelLM/Thor/wiki/GRBL-&-GCode-Control
Hi Leonardo, you can find the firmware files here: https://github.com/angellm/grbl
And here you will find the instructions to compile and flash it: https://github.com/AngelLM/Thor/wiki/GRBL-&-GCode-Control
Hope it helps!
Angel L.M.