Latitude E7450 - unable select a USB port to boot

My Dell Latitude E7450 laptop has a serious issue: when there are more than one USB devices connected, I can't select which one to boot.

The boot menu shows only one "USB Storage Device" when there are 2 bootable USB flash devices connected, as shown below:

This is independently of UEFI/Legacy modes, I have tried _both_ with Secure Boot OFF!

Is there any BIOS tweak to enable multiple USB devices to be shown on the boot menu?

BIOS ver. A16