The official article, the method is very simple, but there are requirements for the U disk, which needs to be compatible.
Only for Raspberry Pi 3
The principle is to modify the /boot/config.txt file of the Raspberry Pi and append a program_usb_boot_mode flag to the back.
After restarting, the Raspberry Pi system will write the flag bit in the OTP memory of the Raspberry Pi according to this flag bit. This memory is internalized in the SOC chip. Once written, it is irreversible.
Then write the system in the U disk according to the conventional method.
step:
Update the system to ensure that the system is a version after 2017-04-10
$ sudo apt-get update && sudo apt-get upgradeEnter in the terminal, modify the /boot/config.txt file of the Raspberry Pi, and append a program_usb_boot_mode flag after it. :
echo program_usb_boot_mode=1 | sudo tee -a /boot/config.txtreboot the system
and enter
$ vcgencmd otp_dump | grep 17:
17:3020000aConfirm whether the output is: 0x3020000a , if not, it means that the flag bit is not successfully written to the OTP memory.
If you think it is necessary, in config.txt, delete the program_usb_boot_mode=1relevant content of the last line you just added.
Otherwise, inserting this SD card into other Raspberry Pi will rewrite the OTP memory of other Raspberry Pi.
Then re-do the system in the U disk.
Follow-up:
At present, it is possible for some people to try the 32G USB flash drive of SanDisk Kudou, but not 64G.
I tested 3 USB flash drives at home and found that the compatibility is not too objective.
One of my friends' DIY USB 2.0 flash drives can support it, but the speed is relatively slow, and I can feel that the system is obviously more stuck than the SD card.
Kingston DataTraveler 100G3 16G, USB3.0, the system can run normally, and the speed is similar to the SD card. Almost, but there is no way to restart after sudo reboot.... It seems to be shut down by default.
There is also a USB3.0 U disk with the fastest speed. After the system is completed, there is no response when plugged in...
For details, please refer to the official article, the entry of the article is deeper, memo, address:
https://www. raspberrypi.org/documentation/hardware/raspberrypi/bootmodes/msd.md