Increase the Laser pulse duration, as it was not firing at 2 or 3ms with low PPI values.
Modify the Laser fire function to disable the timer before re-loading to remove a race condition.
Make sure that the PPI steps are reset after a move. Otherwise the first pulse might be missed.
Patch From C. Trubshaw.
Remove a condition where the stepper isr may be accessing a block whilst the planner is recalculating it.