To allow the Ubuntu USB to boot, the Egton S-Series has further options that need to be changed in the BIOS.
To access the BIOS, press delete or F2 as the machine is starting.
There are different options dependant on the age of touchscreen.
The two below are examples:
Set "Configure SATA as" to "AHCI"
or set "UEFI Boot" to "Enable"
In both examples, press F4 to save and exit.