Entity Framework 6: Turn off Sequential GUIDs

From the changeset linked to that work item, you'll see that the GuidColumnDefault isn't based on any settings, but just returns the default based on the provider type

Looking at this link, it would appear you can set it manually in your migrations though:

// Excerpt from migration in link above:
public override void Up()
{
    CreateTable(
        "dbo.Items",
        c => new
            {
                Id = c.Guid(nullable: false,
                    identity: true,
                    // You would use newid() instead.
                    defaultValueSql: "newsequentialid()"),
            })
        .PrimaryKey(t => t.Id);      
}