[syslinux] Boot device choice

[MONDON Daniel]

Hi everybody!

I've got 2 USB key devices seen USB HDD and USB key.

The bios configuration choice is first to USB key and second USB HDD.

The content of both USB devices is identical! 
I am in live CD configuration.

The boot is starting on the USB key (sdb1) ... and finish on the USB HDD
(sda1).
(The /cdrom is on /dev/sda1)

What is the correct kernel parameter to pass to finish booting on the
syslinux starting device?
(I can have cases with USB HDD full destroyed, and USB key then become
sda1).


Thanks
Daniel.