Hello!
I got another Pi 3+ - used. I booted FreeBSD.
I edited /boot/efi/config.txt
[all] arm_64bit=1 dtparam=audio=on,i2c_arm=on,spi=on dtoverlay=mmc dtoverlay=disable-bt device_tree_address=0x4000 kernel=u-boot.bin
[pi4] hdmi_safe=1 armstub=armstub8-gic.bin program_usb_boot_mode=1
and rebooted.
Although, it still does not boot from the USB thumb device.
It says no storage devices found if the SD card is missing. The USB ttumb stick is being detected in the running FreeBSD.
Is there anything I can check?