I've recently been trying to flash twrp on my Lg Aristo 2, when I ran the code to OEM Unlock a device it came out with the same "FAILED (remote: 'unknown command')". I started my phone back up and it came to a set up screen, I set up my phone and it said it was OEM Unlocked. When I try to flash a custom recovery, or run any command with fastboot at the beginning i get "FAILED (remote: 'unknown command')" and it doesn't work. Can someone please help?

  • adb devices and fastboot devices does show the phone serialno?
    – alecxs
    Apr 28 '19 at 11:39

Seems fastboot is broken or disabled since Oreo.
First you have to downgrade ROM to Nougat. You can flash *.KDZ files with LGUP or LG Flash Tool.


Then it should work as usual:

  • Make sure you have enabled
    System Settings > About Phone > Developer Options > Enable OEM unlock, and
    System Settings > About Phone > Developer Options > Enable USB debugging
  • check adb is working

    adb devices
  • check fastboot is working

    adb reboot bootloader
    fastboot devices

WARNING: Factory reset, all data lost!

  • unlock the bootloader (one of these should work)

    fastboot oem unlock
    fastboot flashing unlock
  • if unlocking was successful, you can test recovery without flashing

    fastboot boot <path>/recovery.img
  • then reboot into bootloader and flash recovery

    adb reboot bootloader
    fastboot flash recovery <path>/recovery.img
  • if you fail on one of these steps, make sure you have installed latest drivers and platform tools dl.google.com/android/repository/…
    – alecxs
    Apr 28 '19 at 12:03
  • fastboot flashing unlock comes out to: (bootloader) Device already : unlocked! OKAY [ 0.003s] Finished. Total time: 0.008s fastboot boot recovery.img comes out to: Sending 'boot.img' (16954 KB) OKAY [ 0.555s] Booting FAILED (remote: 'unknown command') fastboot: error: Command failed
    – Zavier
    Apr 28 '19 at 18:17
  • check path is quoted correctly for example fastboot flash recovery "C:\Users\My Name\Downloads\twrp-recovery.img" edit: ok then your recovery.img might be corrupt, try a different one
    – alecxs
    Apr 28 '19 at 18:29
  • Did that got same error, also downloaded the recovery.img again
    – Zavier
    Apr 28 '19 at 18:38
  • Downgrade your firmware to the LMX210MA forum.xda-developers.com/showthread.php?t=3805141
    – alecxs
    Apr 28 '19 at 20:05

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