I am unable to boot from the USB (3.9.5 version), created from Basic Multilanguage ISO (Desktop 64 bit) on Dell XPS 13 9370 with Secure Boot enabled (and with latest Bios which is 1.16 - just released on 24th of September, which I guess might be relevant). The same USB successfully boots on other computers (e.g. Thinkpads) where Secure Boot is not enabled.
This Dell XPS when trying to boot from USB resets the boot process after a short while (without any information written on the screen) and launches internal Bios diagnostics. However, during this process a log is created on installation USB EFI partition (in Dell directory) that contains the following line:
[Operating System Loader signature found in SecureBoot exclusion database (‘dbx’). All bootable devices failed Secure Boot verification]
Other Linux distributions (I tried Ubuntu 20.04 and Linux Mint 18) boot without any problems.
Unfortunately I cannot disable Secure Boot on this machine.