Hit F2 at power-on to get into the AMI BIOS. This describes itself as the Aptio Setup Utility.
Alternatively the F12 key brings up a boot menu.
The opening page of the BIOS settings includes:
BIOS Vendor American Megatrends Customised by Fujitsu Core Version 5.0.0.13 Compliancy UEFI 2.6; PI 1.4
Having noted this you then need to click on the 'System Information' entry just below it. This brings up a screen that starts:
System Information Board and Firmware Details BIOS Revision R1.10.0 Build Date and Time 06/05/2019 xx:xx:xx Board D3543-A11 ....
Note: I didn't note the time, hence the xx's above
Alternatively, having booted a copy of Tiny Core Linux, the boot message file includes the line:
DMI: FUJITSU FUTRO S940/D3543-A1, BIOS V5.0.0.13 R1.10.0.SR.4 for D3543-A1x 06/05/2019
Checking the Fujitsu website I found the current BIOS to be
V5.0.0.13 - R1.13.0 23/09/2022.
There are two downloads of the BIOS on offer. The second (smaller) download assumes that you are running Windows on the S940. My S940 had been wiped clean and so the larger (ADMIN) version was required.
The BIOS update process is straightforward and covered in the accompanying readme file. Essentially you unzip the downloaded file to a USB drive/stick, use the F12 option to boot it on the S940 and then follow the on-screen prompts.
There are a lot of options in the BIOS. Picking on a few of them
On power-up the F12 brings up a boot option screen which shows a list of whatever bootable items it finds. In this example I had a Sandisk USB pen drive plugged in to one of the front USB ports and a wiped internal flash drive:
Please select boot device:UEFI: SanDisk Cruzer Blade 1.26 Diagnostic Program Enter Setup↑ and ↓ to move selection ENTER to select the boot device ESC to boot using defaults
Some of these options (eg UEFI) will depend on what you've enabled or disabled elsewhere in the BIOS.
Going to the Fujitsu support site it looks the options might be:
Under the S900 Firmware tab I noted a way that you can reset any BIOS Administrator password for the S900 and some other Fujitsu thin clients. I do not know whether this is equally applicable to the S940 and I haven't seen any mention of it in the documentation I have seen.
If your S940 has an Administrator password set you might like to experiment with this.
I also note the BIOS manual includes:
Password Severity
Defines ways to access the system if the password has been forgotten.
Standard A forgotten password can be deleted using the Password skip jumper.
Strong It is not possible to use the Password skip jumper. If a password has been forgotten, only the certified, technical support team can enable it.