Comment # 6 on bug 1179170 from Gary Ching-Pang Lin

(In reply to Michael Chang from comment #5)
> (In reply to Gary Ching-Pang Lin from comment #4)
> 
> > It sets immutable to 0 and unlinks the path. In
> > kernel/drivers/firmware/efi/vars.c, when removing a file, it uses
> > uefi_set_variable() with NULL to delete the variable, and this is unlikely
> > to fail.
> 
> Yes that is where I'm looking at. There's no obvious system call made
> besides ioctl to set the immutable flag would return invalid argument.
> 
> > Maybe there are more clues in /var/log/pbl.log.
> 
> Maybe we should enable verbose output to collect more info ?
> 
> Index: efivar-37/src/efivar.c
> ===================================================================
> --- efivar-37.orig/src/efivar.c
> +++ efivar-37/src/efivar.c
> @@ -63,7 +63,7 @@ static const char *attribute_names[] = {
>         ""
>  };
> 
> -static int verbose_errors = 0;
> +static int verbose_errors = 1;
> 
>  static void
>  show_errors(void)

It'd be better to set the verbosity from efibootmgr like this:
https://github.com/rhboot/efibootmgr/blob/master/src/efibootmgr.c#L1675