I have an Etherminal 5js with the same MB since yesterday.
To boot from disk or getting access to the system's bios, pull out the DiskOnChip Flash-Rom-Module. It has a socket like an IC.
Take care of it's orientation.
Then the machine will have a behaviour like a normal PC, what it used to be.
It's CPU ist an AMD 5x86 (or 586) running with 133MHz.
The onboard-graphics is Cirrus-Logic-like with 2MB VRam. It should make a resolution of 1280x1024@75Hz with 256 colours.
The Sound-system ist a SB16-clone.
Ethernet is 100Mbit.
In my machine the FlashRom ist 12MB and contains a tiny Linux (kernel 2.0 and X11R6) with Netscape 4.
And... a root-password, that I don't know
So I have to examine the FlashRom with an universal-programmer to remove it.
Here you should find some Informations: