[syslinux] syslinux.cfg, default, labels

[gxhniip421zw at posteo.de]

Hi,

http://www.syslinux.org/wiki/index.php?title=Config
> DEFAULT
> 
>   DEFAULT command
> 
> Set the default command line (which often references a LABEL). 

I have tried

  default vmlinuz-4.12.13_1 root=.... rootflags=.... initrd=....

but vmlinuz does not get executed.
I was given a prompt ("boot:"). Despite that "prompt 0" and "timeout 0" are present in the cfg.

With using a label and, after the label, "linux" + the above command line, vmlinux does get executed fine.

So, *is the use of labels mandatory?*...


(This is on linux, booting is via extlinux.)


What is the absolute shortest syslinux.cfg when I want to just start immediately the vmlinuz? No menu, no prompt, no implicit command line, no keystroke watching, no autocompleting.

The 'ontimeout' is the same as 'default', or is there any difference? Only one of them can be present?