Install hang on dual boot machine - vfat in scsi7 partition #2 (sdb) at /boot/efi

[tea for one]

When you have booted into a live Ubuntu session, you can double check whether you are in UEFI mode or Legacy mode.

Open a terminal and enter:-

[ -d /sys/firmware/efi ] && echo "UEFI mode" || echo "Legacy mode"

[oldfred]

Again the UEFI boot mode is only for your installed system.
How you boot install media is how it installs.

Every brand UEFI is different, but screen shot shows two entries for Toshiba flash drive. One clearly UEFI and one not.
My UEFI is somewhat similar as it shows two entries, also, but is a totally different brand UEFI and different source for live installer.