- About statement of the Raspberry Pi Foundation on Raspberry pi 4
Network and USB boot Support for these additional bootmodes will be added in the future via optional bootloader updates. The current schedule is to release network boot first, then USB boot.
More detail please refer to: https://www.raspberrypi.org/documentation/hardware/raspberrypi/booteeprom.md and https://www.raspberrypi.org/documentation/hardware/raspberrypi/bootmodes/msd.md
But USB mass storage boot is available on Raspberry Pi 3B, 3B+, 3A+, and 2B v1.2 only.
- This is a third-party solution, not the official Raspberry Pi Foundation.
X825/X855/X856/X857 Allows booting OS from your HDD/SSD for faster app opens, web serving and file copying , A micro SD card is required for forcing the Raspbian OS to use the HDD/SSD for its "root" partition
Please refer to : https://www.tomshardware.com/news/boot-raspberry-pi-from-usb,39782.html
