Unsure whether this is the correct forum.
I am running Ubuntu 16.04 LTS on my Dell Inspiron Laptop - no other OS.
I want to use TAILS as a mobile OS via a Flash Drive when required.
I have just checked the laptop boot order which shows EUFI SECURE BOOT 'ON' plus just 'UBUNTU' and 'WINDOWS BOOT MANAGER' as boot options [I had W10 on this laptop but have removed it a while back].
I will admit that I find EUFI very confusing !
Can someone advise please how I go about changing the boot order so that an inserted bootable FlashDrive [containing TAILS] will boot when the laptop is switched on but UBUNTU will boot when no FlashDrive present - as it does now.
Thanks,
MikeO

When you boot whichever type computer you have, you should see a message on screen telling you which key to use to access BIOS and or boot options. This varies greatly by manufacturer so you will just have to watch the screen. You should see your flash drive listed so just select it. You may also be able to run sudo update-grub when booted to Ubuntu and your flash drive plugged in. This worked for me to detect Linux systems on an external flash drive but I don't know if it will work for Tails.

I don't believe Tails currently is capable of booting when secure boot is turned on. I know they planned on implementing this, but not sure that it's been done.

Thanks guys.
I will follow up on the Tails vs Secure Boot issue.
As I am somewhat confused by UEFI, cannot secure boot be turned off - not sure sure with my use of my Laptop whether I need it at all. Or dont I have an option ?
Re accessing BIOS/Boot Options thats not a problem [F12 for me], I am just unsure of what process to follow to enable booting from a flash drive unlike the 'old days' when we could change the boot order very easily. All I have now is 'UBUNTU" and 'WINDOWS BOOT MANAGER' but no entry for FlashDrive !
MikeO

Secure boot can be turned off. It's not necessary. It simply prevents anything from booting that doesn't have a signed kernel and bootloader. While good in theory, M$ was allowed to control it, so it's basically worthless as a security and is more of a tool to prevent people from using the OS of their choice as only copmanies that have deals with M$ can get their bootloader & kernel signed, or you can sign your own to be able to boot any OS.

For Dell laptops, the F2 key typically gives you access to BIOS settings (where you can disable secure boot), the F12 key typically gives you access to the menu of bootable devices.

Try disabling secure boot in the BIOS, then check if the TAILS drive is in your list of bootable devices in the boot menu when you press the F12 key during initial boot up. If the TAILS drive is not appearing there, you need to make sure that the USB drive is bootable. You cannot simply copy an ISO file to a usb drive and be certain that it will boot. Something like tuxboot or unetbootin can be used to make a bootable USB drive from an ISO file in Linux. There is also a multi-platform tool called etcher: https://etcher.io/.

Thanks everyone.
I think I have enough info to be going on with.
Will follow up at this end and if I run into problems I will post again.
MikeO