Changes

Yes. Please refer to [https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#updating-the-bootloader]* About [https://www.raspberrypi.org/documentation/hardware/raspberrypi/booteeprom.md statement of the Raspberry Pi Foundation] on Raspberry pi 4<pre>Network and USB bootSupport 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.</pre>

OK, Raspberry Pi Foundation release '''BETA version to support USB boot''' on May. 2202, please refer * Refer to [https://www.raspberrypi.orgcom/documentation/hardware/raspberrypicomputers/bcm2711_bootloader_configraspberry-pi.md Pi 4 html#updating-the-bootloader Updating the Bootloader Configuration]， TESTED!  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.OR* User guide: [https://www.tomshardware.com/how-to/boot-raspberry-pi-4-usb How to Boot Raspberry Pi 4 From a USB SSD or Flash Drive]