I recently retired my dinosaur Flashforge Creator Pro and got an Ender 3 S1 Pro. It's my first 3D printer with auto leveling. I've followed all instructions and online guides and am running into some trouble.
One very confusing topic is a Youtube video that mentioned the M420 script. Until today, I thought the Ender would create the adjustment mesh with auto-leveling and use it by default for printing. The video mentioned that it doesn't actually do anything unless M420 (use the mesh adjustments stored in the printer's firmware) or G29 (conduct auto leveling and use the new mesh adjustments) is added to the starting script.
Can anyone verify whether or not this is true? I know how to input the lines of code and the explanation for what they do (at least I think I do). I just find it hard to believe that the feature is basically useless without the script adjustment. It's a fairly modern and common printer and I don't see documentation about this anywhere while everything seems to point to the mesh being used automatically each print. Is there a way to tell accurately and not just with success/failure if the mesh adjustments are being used while printing? If the script is necessary, why would it not be included by default in the machine's S3D profile? And finally, is this the case for all auto-leveling printers or just this particular model/series?