Make sure the controller is reporting positions in mm, as expected by LightBurn ( $13=0).Set your machine status reporting to be relative to the workspace origin, not the machine origin ( $10=0).If your machine uses negative workspace coordinates you'll need to apply a workspace offset ( G10 L2 P1 xx yy).

The pause, which happens on older versions, or when not using Laser Mode, will cause excessive burn spots when engraving images. If you have an older version of GRBL (prior to 1.1f) it's highly recommended to upgrade the firmware, as Laser Mode also prevents the machine from pausing with every power change.You might need to enable 'Laser Mode' if you have GRBL 1.1f or later ( $32=1).The value in LightBurn is called 'S-Value Max', in the Device Settings. You might need to adjust your spindle max RPM value ( $30) to match the LightBurn default (1000) or vice versa.If you have a GCode-based system, like a Shapeoko, Eleksmaker, X-Carve, or Acro system, you might need to make some simple changes to get the most from LightBurn.

Lightburn software code