Tested on Raspberry Pi 4 B 8GB.
Download 14.1-RELEASE arm64 RPI and make a bootable microsd card.
Update firmware using `rpi-eeprom` via Raspberry Pi OS.
```
sudo apt update && sudo apt install rpi-eeprom
sudo rpi-eeprom-update -a
```
Make rpi-firmware and install
```
cd /usr/ports/sysutils/rpi-firmware
make install
cp -pr /usr/local/share/rpi-firmware/* /boot/efi/
```
Make latest u-boot-rpi4 and install
```
cd /usr/ports/sysutils/u-boot-rpi4
make install
cp /usr/local/share/u-boot/u-boot-rpi4/u-boot.bin /boot/
```
or
```
cd /usr/ports/sysutils/u-boot-rpi4
make install
cp /usr/local/share/u-boot/u-boot-rpi-arm64/u-boot.bin /boot/
```
Reboot.
```
freebsd@generic:~ % uname -a
FreeBSD generic 14.1-RELEASE FreeBSD 14.1-RELEASE releng/14.1-n267679-10e31f0946d8 GENERIC arm64
```
If a red screen appears, update the firmware first. If a rainbow screen appears, set `hdmi_safe` to `0` in the `config.txt` file.