laser bug

[officine080]

hi,
I'm using marlinkimbra to control a lasercutter since my controller (mpc6515) has broken.
The laser tube is a 80w c02. dimensions are 1380 x 880 mm.
I can generate a gcode using inkscape and the modified turnkey laser plugin.
Using pronterface I can turn on and off and set the intensity of the laser beam using M3 M4 and M5 commands. But, if I load a gcode with m5 at the end, the laserbeam remain on. if i edit thath gcode and substitute m5 with m81 the laserbeam turns off.
@nextime

[officine080]

i've also problems with raster engravings and small arc being splitted in small segments.