The 44xx has an interesting BIOS. When you get into it the top line of the screen identified it as InsydeH20 Setup Utility Rev. 5.0. In the Linux dmesg text I find the line:
DMI: 10ZiG Technology. 44xx/44xx, BIOS 44xx V:3.2.21-04172015 04/17/2015
I also found that the BIOS on the 4448C was password protected. Trying the password 10ZIG got me in.
Hit the ESC key on power-up to get to the startup screen. This is shown below.
There are six icons shown on the screen with the currently selected one being highlighted.
The Boot Manager screen lets you pick the boot device for this particular boot. In
this particular case the internal flash (SEM04G) is highlighted. There is a USB pen drive
plugged in.
I find that in the Device Management screen I can do virtually nothing. The only
option appears to be to toggle the Primary Video BIOS entry between PCI and AGP.
I don't know exactly what the File explorer is looking for. This is what it shows with
the onboard flash and a USB pen drive with Tinycore 9.0 installed on it.
This is the Administer Secure Boot screen. I haven't tried anything here.
This is the conventional BIOS setup. To get into it I had to use the default BIOS password
of 10ZIG. (Note upper case).
An example from the Boot setup in the BIOS screen. Note the option there to enable/disable
the ability to boot from a USB device.
Setting the boot order sits under the >Legacy menu item.
I haven't investigated exactly what the standard Zero Client firmware offers other than it is Linux based.
I'm so used to manufacturers like HP or Wyse who have extensive support pages from which you can download the original firmware, find updates to the firmware and the latest BIOS that the 10ZiG site comes as a bit of a shock....
The 10Zig website has no obvious download section or support contact - the only immediately obvious thing being a support FAQ that appears under the Resources tab. I note that when you mouse over the 'Contact' tab you get two drop down options: 'Become a Reseller' and 'Career Opportunities'. However, if you actually click on the tab, a new page does appear and down the page there are a couple of email addresses for support.