What is the best way to print a model with support material in first layer?
I had the same problem printing a miniature just recently.  As always, settings are somewhat dependent from the object you want to print, but here are some suggestions:


Increase the support density: 15% (8% is very low!)
Support pattern: zig-zag with "connect zig-zag" option enabled (add stiffness to the "column" of support)
Enable support interface (increase adhesion to the plate, and provide a more "beefy" base for the support material)


For reference, here's a screenshot of my settings as I tweaked them for that miniature (printed a 0.1mm layer height).



("Support line distance 1mm" is the same as "Support density 15%", or at least it is the same with my nozzle size)

If your problem was not only with the "flakiness" of the material, but also with it adhesion to the bed, then prepping your printing bed somehow (with a bit of painter tape, glue, etc... can help.  Alternatively using a brim or a raft (as also suggested by another responder) could also help.

EDIT: all the above still standing true, it turns out the OP had a hardware problem as well, his timing belt being loose (see comments).