Failed (remote: Dtb Not Found) In Cmd Fastboot Boot Twrp.img

Aug 25, 2018
I believe you have the same problem i had due to locked bootloader.
Can you check once again with "fastboot oem device-info" if your bootloader is unlocked?
Right on, my bootloader seems to be locked:

fastboot oem device-info returns
(bootloader) Device tampered: false
(bootloader) Device unlocked: false
(bootloader) Charger screen enabled: false

How do I unlock it ?