Accessing legacy BIOS

Hello,
I'm my witt's end how to get into my legacy BIOS and set the boot priority to USB.
Old Toshiba TECRA R850 updated to w10 x64 pro from 7.
Tried ESCP, F1, F2, F10, F12, Delet, no luck.
Any ideas?
Thank you
barsim

Ghot said:

@barsim2


For the Toshiba Tecra the BIOS key is... F1 or Esc

And the Boot Menu key is... F12






When you start or have rebooted the computer... try gently spamming the correct key.
Like twice every second.

Neither f1, escp worked after start or reboot.

admin cmd prompt:
shutdown /r /fw /f /t 0

SIW2 said:

admin cmd prompt:
shutdown /r /fw /f /t 0

Dear SIW2
The admin cmd says

C:\WINDOWS\system32>shutdown /r /fw /f /t 0
Boot to firmware UI is not supported by this system's firmware.
the
One more info: this problem (accessig the legacy bios) present since I had to Reset my Win 10 because Ashampoo backup Restoration did not do its job.
Thanks

detach any bootable devices and it will have to go into bios.

SIW2 said:

detach any bootable devices and it will have to go into bios.

did not any bootable device in while tried

SIW2 said:

admin cmd prompt:
shutdown /r /fw /f /t 0

That only works with UEFI firmware, not legacy BIOS.