[syslinux] Alternating boot default entry every reboot

[Brendon Costa]

Hi,

I am currently using isolinux (syslinux-6.03) in a clonezilla setup. It
boots fine, however I want to have a setup where the default boot selection
alternates every boot.

* First boot : Default is menu item 0
* Second boot : Default is menu item 1
* Third boot : Default is menu item 0
...

The idea is that when it is booted into clonezilla the clonezilla script
checks if the system needs to be restored by mounting NFS and checking for
existence of a file. After clonezilla has restored it will reboot and then
the isolinux will boot the native file system (Windows, OSX or Linux). Once
the native OS has restarted, then isolinux will again boot clonezilla and
the cycle continues every time you reboot.

I have this clonezilla + isolinux installed on a bootable USB.

I know this is possible with GRUB:
http://unix.stackexchange.com/a/110539

however from what I understand GRUB will not work correctly from the
bootable USB on all hardware, which is why we use isolinux.

1) Is there any way I can achieve this currently in isolinux that I did not
see looking at the docs?

2) If not, is this possible (obviously not possible for read-only CD, but
bootable USB I imagine yes) and would a patch be welcome to support such a
feature?


Thanks,
Brendon.