boot - Can't detect Wily bootable USB stick under UEFI

I hope this is not too much of a duplicate, I tried checking out old questions and answers but without luck, UEFI has been giving problems for 3+ years now but still I struggle with it.

Here's the situation: I have an ACER Aspire VN7, I am trying to install Ubuntu 15.10 on it with dual boot (leaving the original windows 10 aside). But I can't succeed making the pc see the Ubuntu USB stick, no matter what.

As advised, I disabled Windows quick startup from the control panel, disabled the security lock in the BIOS (but there doesn't seem to be any quick startup option to disable there), but still the machine will ignore the bootable USB stick altogether.

I also tried Rod Smith's rEFInd alongside, as he suggested on some old answer. The result is that my pc boots on rEFInd as it should but still ignores the Ubuntu USB (not even within rEFInd does it show up as an option).

I managed to successfully boot from the same Ubuntu 15.10 USB stick after switching the BIOS boot to Legacy instead of UEFI, but UEFI has been standard for Windows for at least 3 years now and I would definitely prefer if a UEFI solution could be found.

I will be very grateful to anybody who could provide advices or insights!

How did you prepare the USB drive? Some programs for writing .iso files to USB flash drives omit EFI boot loaders and so won't work for booting in EFI mode. Some have options that affect bootability. Some create USB flash drives that work OK on some EFI-based computers but not on others. In short, you may need to try another program. I have notes on several programs here. In brief, Rufus under Windows seems pretty flexible and reliable. From Ubuntu, I generally use dd, but some people like UNetbootin. Even if you use a program that's generally reliable, though, it might be failing for your computer, so you may need to try something else.

If you are forced to do a BIOS/CSM/legacy-mode install, I recommend doing it as follows:

1. Launch the installer in its "try before installing" mode.


2. Open a Terminal window.


3. Type ubiquity -b. This launches the installer and tells it to not install a boot loader.


4. When the installation has finished, boot with the rEFInd USB flash drive you already have. It should detect your Ubuntu installation and enable you to boot it.


5. Install the EFI-mode version of GRUB (in the grub-efi package), rEFInd, or any other boot loader you like to the computer's hard disk. This should enable you to boot without the rEFInd USB drive.

Upon re-reading your answer, it's unclear if you used rEFInd on a USB drive or installed it from Windows. If the latter, you may need to install an EFI filesystem driver for your Ubuntu filesystem (ext4fs by default), but if you're happy with rEFInd, you won't need to re-install it.