I found the F2 key got me into the IGEL D220 BIOS which identified itself as InsydeH20 Setup Utility. I first encountered this in the 10ZiG 58xx. It is also in the M320C and M330C, but not in such an extensive form.
The opening screen shows four icons which are labelled:
What they do is self-evident. In this context I assume SCU stands for System Configuration Utility. Selecting that gets you into the BIOS setup screens.
In BIOS setup screens the Boot Type can be set to one of three options:
In the Legacy settings there's an entry for Boot type order which in my case brought up:
Alternatively, on reset/power-up, the F9 key gets you into the Boot Manager.
With the current setup on my D220 and with a flash drive plugged in to one of the USB ports the Boot Manager display was:
Boot Option Menu
Legacy USB
USB2.0 FlashDisk
Legacy Hard Drive
TS2GSSD25H-S
↓ and ↑ to change option. ENTER to select an option. ESC to exit
As usual I haven't done anything with the native operating system.