I am following the instructions from freebsd to boot FreeBSD - RISC-V image booting on macOS Sequoia 15.2 with brew installed qemu :

qemu-system-riscv64 -machine virt -m 2048M -smp 2 -nographic \
    -bios /usr/local/share/opensbi/lp64/generic/firmware/fw_jump.elf \
    -kernel /usr/local/share/u-boot/u-boot-qemu-riscv64/u-boot.bin \
    -drive file=FreeBSD-15.0-CURRENT-riscv-riscv64-ufs.raw,format=raw,id=hd0 -device virtio-blk-device,drive=hd0 \
    -netdev user,id=net0,ipv6=off,hostfwd=tcp::8022-:22 -device virtio-net-device,netdev=net0

and I get :

qemu-system-riscv64: netdev: drive with bus=0, unit=0 (index=0) exists

I also tried :

qemu-system-riscv64 \
-M virt \
-drive file=/opt/homebrew/share/qemu/edk2-riscv-code.fd,format=raw,if=pflash,readonly=on \
-accel hvf \
-cpu host \
-smp 6 \
-m 50G \
-drive file=FreeBSD-15.0-CURRENT-riscv-riscv64-ufs.raw,if=virtio,cache=writethrough,format=raw \
-serial mon:stdio \
-nographic

and got :

qemu-system-aarch64: /opt/homebrew/share/qemu/edk2-riscv-code.fd,format=raw,if=pflash,readonly=on: drive with bus=0, unit=0 (index=0) exists

(found the second command elsewhere on the internets)

Any ideas ?