Sounds like your CW-4000HD is one of the versions that will require a BIOS update.
You can download it from here: cw-lmc-bios_update.iso.zip
The BIOS image is an ISO. Unzip the file to get the ISO.
You will need to burn it to a CD just as you would the recovery image. i.e. do not burn a data CD with it. It will not boot if you do.
To update the BIOS you will need a keyboard. The first step is to simply insert the CD and reboot the system. Press F11 to get the boot menu and choose the CD. The BIOS will be updated and the system will reboot on it's own. DO NOT INTERRUPT THE PROCESS.
You will then see a new bios splash screen. It will say "BIOS Version 2.5" below the CaptiveWorks logo. On the first reboot you will get a message that states the CMOS checksum is bad. Press F2 to set the defaults and continue. You do not need to enter the BIOS setup. You will also see another error on the first boot regarding EHCI and a BIOS error. Don't worry about it. You will not see it again. If you do let us know