When trying to upgrade the firmware on a ML100 or DL100 range server (e.g. DL180, ML115) server you may run into an issue that the ROMPaq doesn’t boot and only displays the message “Starting Caldera DR-DOS….” the servers then seems unresponsive. After trying different versions, different USB keys and a new motherboard the issue was rectified by completing the following.
Locate the four switches on the mother board underneath the riser card, between the USB slot and SATA connector.
Set all 4 of the switches into the off position and then use the onboard USB to load the required firmware. There should be no need that I have found to put these switches back into the original configuration.
Virtualised Reality 
got the same problems. Thanks for sharing