hi all . i read https://www.raspberrypi.org/documentation/hardware/raspberrypi/bootmodes/msd.md
and i succeed to boot raspbian only bu usb memory . usb harddisk may be OK . and this experiance may contribute to arm of openbsd . so i send this mailing list . 1) boot raspbian by sd 2) rewrite /boot/config.txt dtoverlay=hifiberry-dacplus dtparam=audio=on program_usb_boot_mode=1 3) reboot raspbian by sd acertain vcgencmd otp_dump | grep 17: # > 17:3020000a 4)halt raspbian ------------------------- 5) i use archlinux PC insert sd to this PC and insert USB memory to this PC 6)now sd state Device Boot Start End Sectors Size Id Type /dev/sdd1 8192 93596 85405 41.7M c W95 FAT32 (LBA) /dev/sdd2 94208 27277311 27183104 13G 83 Linux /dev/sdd3 27277312 31422463 4145152 2G 82 Linux swap / Solaris so i do partitioning USB memory , as followings fdisk -l /dev/sde Device Boot Start End Sectors Size Id Type /dev/sde1 2048 206847 204800 100M c W95 FAT32 (LBA) /dev/sde2 4401152 61702143 57300992 27.3G 83 Linux /dev/sde3 206848 4401151 4194304 2G 82 Linux swap / Solaris 6) mount /dev/sdd /md1 mount /dev/sdd2 /md2 mount /dev/sde1 /me1 mount /dev/sde2 /me2 rsync -avHx /md1/ /me1/ rsync -avHx /md2/ /me2/ 7)rewrite /me1/cmdline.txt dwc_otg.lpm_enable=0 console=serial0,115200 console=tty1 root=/dev/sda2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait quiet splash plymouth.ignore-serial-consoles /me2/etc/fstab proc /proc proc defaults 0 0 /dev/sda1 /boot vfat defaults 0 2 /dev/sda2 / ext4 defaults,noatime 0 1 /dev/sda2 none swap defaults 0 0 /me2/etc/rc.local _IP=$(hostname -I) || true if [ "$_IP" ]; then printf "My IP address is %s\n" "$_IP" fi sleep 30 service dphys-swapfile stop exit 0 8) umount /md1 /md2 /me1 /me2 9)insert only usb memory and switch on raspbian boot ------------- regards
