The 59xxq BIOS is identified as an InsydeH20 BIOS.
Like the 58xxq on power-up the DEL key gets you into the BIOS or the ESC key into a startup screen where you can select:
The two of interest here are the Boot Manager that lets you manually select your boot device, and SCU (System Configuration Utility) to edit the BIOS settings.
The BIOS supports both Legacy and EFI booting.
As with many modern thin client BIOSs there are not a huge number of settings to play with. You can enable/disable various controllers (Audio, SATA, USB etc), set/change passwords, set 'wake-up' events and set Boot type (Legacy/EFI/both) and priority (EFI,LAN,USB,....).
Having booted Tiny Core I find in the dmesg output:
10Zig Technology 5900q/Type 2 - Board Product Name, BIOS V:3.2.21B-03092018 03/09/2018
See the 58xxq entry for some of the typical BIOS screens.
Although our interest in a device like this is in using it as though it were a general purpose computer do remember that is not 10ZiG's intent. They have a much narrower view and are delivering the hardware with their own tightly focussed thin client OSs. The BIOS tends to reflect this and various options you might hope to tweak are just not there.
For example the CPU supports Intel Virtualisation Technology but there is no BIOS setting to enable or disable this feature.
An example of what I mean can be seen under BIOS Patching in the entry for the Igel M340C.