NOTE: If none of this works, then the data on the drive may not be correct or not correctly installed for your device.
NOTE: Before you set boot priority for a USB device, plug the device into a USB port.
To specify the boot sequence (as in what order the drives load in)...
1. Turn on the computer and then, during the initial startup (first or second screen), press ESC, F1, F2, F8 or F10 (depending on which your device uses to get to BIOS).
2. Now enter BIOS setup. (It can mistakenly be called Aptio Setup sometimes because that is the title in the screen, but this is BIOS).
3. Use the arrow keys and select the BOOT tab. You should now see "System devices" shown in order of priority (which starts up when).
4a. To give a cd or dvd priority in the sequence over the hard drive/hdd/sdd, move it to the first position in the list.
4b. To give a USB priority in the sequence over the hard drive/hdd/sdd, do the following...
A. First move the hard drive/hdd/sdd to the top of the boot sequence list.
B. Open the hard drive/hdd/sdd device in the list and it should display all hard drives.
C. Now move the USB device to the top of the list of hard drives.
5. Now save and exit the BIOS setup utility.
6. The computer should now restart with the changed settings.
Now if you want to set the boot priority using a device selection menu...
1. When the computer first starts to boot up, just after the manufacturer's logo screen, press F12 (probably a few times, in quick succession).
2. The device selection menu should show up now.
3. Use the up and down arrows keys to select CD, DVD or USB Flash Drive.
4. To set it to boot from the selected device, press ENTER.
Thanks for the reply. Problem is, none of this will work as there is nowhere in the bios boot options to set the boot priority to anything other than the eMMC. I have the USB drive inserted before powering on (in fact, I thought it had to be done this way; I've always done this on any machine booting from USB.
I've tried two USB drives from different brands. One contains Ubuntu 18.04.4 and the other has Windows 10 1909 which I used to build a desktop machine a couple of days ago. Both drives work in other machines. Neither drive works in the laptop in question.
Yeah, I wondered about this. USB support shows as enabled, and the ports do appear to be working as the USB stick is visible if I run the EZ Flash utility. Since the stick shows up here I thought I might as well flash the bios. The laptop is now running bios version 314 but unfortunately this hasn't made any other options visible and still won't boot.
Slight update: I did manage to get it to boot from the stick once using Windows boot manager, but I then made matters worse when I tried to install Ubuntu; the process failed part way through so now the thing has no OS installed at all...