ThinkPad X250 BIOS update from USB boot disc

I am doing this because I am unable to set a BIOS password to my Thinkpad x250 i did everything that can be done and a BIOS password could not be set for some unknown reason I started to believe it is a BIOS bug. So my BIOS was 2015 and from lenovo I saw newer 2020 BIOS updates so i downloaded these updates. But to continue from here is unknown. It seems, that I have to create a USB boot disk from an iso file so that I can upgrade my BIOS. After the BIOS upgrade, I am now able to secure my laptop by setting a BIOS password.
Get the iso from here pcsupport.leno...
In my case it is n10ur27w.iso. I already re-formatted the Thinkpad to Linux so I don't have Windows OS anymore.
From an ubuntu, I make a bootable USB from this iso.
1) geteltorito -o x250.img n10ur27w.iso
2) dd if=x250.img of=/dev/xxx bs=1M (know your usb drive mount)
3) Goto Thinkpad x250 BIOS and temporarily set boot to "UEFI Only" otherwise USB will not boot.
4) Insert USB drive to usb port and turn-on press F12 select usb drive. You shall see the menu and proceed from there. The laptop will make a reboot and actually does the flash updating on the next boot. DO NOT DISTURB this flow!!!

[@oblivionrecorder]

Hello, after flashing, does your BIOS version number end with a P?