Hit F2 at power-on to get into the BIOS that identifies itself as "Insyde Software SCU". (On boot up it identifies itself as "Insyde Software MobilePRO BIOS 4.20.00").
Unusually the BIOS menu does have a 'Version' option under the 'Exit' drop down menu. This reports BIOS version 1.05.05 Date: 05/16/05.
The boot options that can be set are:
You can also get straight to these options by hitting the F12 key.
Separately you can set the IDE boot order. With a pen drive plugged in to a USB port this showed:
The FC128 is the on-board 128MB Compact Flash card.
Note: If you bring up the boot menu with the F12 key you only have the four basic boot options. You cannot select which IDE device it will boot from if that's your choice.
I used the PageUp key to move the pen drive to the top of the list.
My standard Tiny Core 6.1 pen drive with Syslinux as the boot loader booted quite happily.
My S300 runs eLux NG.