How to boot linux

I tried to boot linux with the instruction https://github.com/96boards/documentation/wiki/DragonBoard-820c-Getting-Started-With-Linux. I download the boot image from the web. But it failed to boot.
$sudo fastboot boot boot-linaro-stretch-qcom-snapdragon-arm64-20170803-71.img

[47220] boot_verifier: Device is in ORANGE boot state.
[47220] Device is unlocked! Skipping verification…
[47230] LK SEC APP Handle: 0x1
[47230] Return value from recv_data: 14
[47240] Return value from recv_data: 14
[47250] Return value from recv_data: 14
[47260] LK SEC APP Handle: 0x1
[47270] <8>keymaster: "“qsee_stor_device_init error ret: -14"”
[47280] <8>keymaster: "“len: 48"”
[47280] <8>keymaster: "“boot state: 48"”
[47290] <8>keymaster: "“is_unlocked: 1"”
[47290] <8>keymaster: "“color: 1"”
[47290] <8>keymaster: "“system_version: 0"”
[47300] <8>keymaster: "“system_security_level 0"”
[47310] DTB offset is incorrect, kernel image does not have appended DTB
[47310] Device info 0x000000f6/00030001/0x00010001/0, pmic 0x20009/0x10113/0x0/0x0

Anyone can help on this issue?
Thanks