I have recently purchased an Acer Revo One RL85. It came pre-installed with Windows 8 which I have upgraded to Windows 10. I chose the option to use a separate installation USB stick. I repartitioned the drive to leave room for ubuntu linux. The Windows 10 installation was fine.
In the space left over I installed Ubuntu Linux 16.04 (I was able to boot from a USB stick). The installation was fine.
When booting, I am not presented with any way to choose the operating system to launch - I am only presented with the "Windows Boot Manager". I have searched various other forum threads and there is mention of "trusting" the Ubuntu EFI boot files. All the forums indicate that I need to enable a Supervisor Password in the BIOS (which I have). Doing so should, apparently, allow me to navigate to the Ubuntu Linux EFI files with the "Boot" tab in the BIOS. This facility does not appear to be available.
The BIOS version is as follows:
Build Date: 01/09/2015
Build Date: 01/12/2015
I can supply further details (e.g. partition layout; files installed into the UEFI partition etc) if required.