Historically, booting a Raspberry Pi required an SD card. However, if you follow [tynick’s] instructions, you can get a Pi 4 to boot from the USB port. Combine it with a small solid state disk ...

plug the SDWire into a MicroSD slot of your embedded device, and then connect a USB cable from the SDWire to your development computer. This way, if you need to reflash the firmware on the SBC you ...