The BIOS on my new desktop does not seem to be able to boot from a Linux installation I have recently loaded on one of my hard-drives.

Tower 7910 arrived with 4 HDs connected with Windows 8 pre-installed on them.  The HDs were controlled by the SAS RAID controller, everything booted and ran fine.

I would like to use this machine to run Ubuntu 14.10.  I created an installation USB and booted with that, I could see the HDs, installed to those successfully, however upon reboot, the BIOS does not recognise the new Linux installation as being bootable.

After scratching my head for a few days, I wondered if this was due to the fact that the HD I installed to was controlled by the SAS RAID controller.  So I winkled a SATA cable that does not use the SAS bays from the case and installed Linux onto a separate HD connected to the motherboard separately from the SAS controller.  This works fine (can install Ubuntu on this drive and the BIOS immediately recognises it as bootable, and I can boot from it and even verify that Ubuntu was successfully installed on the original HD).

I have also tried to update the BIOS to the latest version I downloaded from dell.com/support in the hope that this would allow me to boot from these HDs.   The version available for download seems to be an earlier version (A01) than the one that the machine came with (A02) but I proceeded with the downgrade anyway and this did not improve the situation.

Unfortunately I cannot see any way of mounting this extra drive into my case (although there is space for more drives, there is no more plastic to allow the HDs to slide into the case).  How can I add HDs to this machine?

Ideally I would like to be able to just boot Ubuntu from the RAID controlled HDs.  How can I do this?