I've been trying to root my HTC U12+, and I've been stuck trying to boot twrp onto my phone through adb commands.

.\fastboot boot twrp.img
Sending 'boot.img' (32424 KB)                      OKAY [  2.006s]

This is what I'm stuck on, my phone screen says "flash images success 1/1)" When I know it's more than one step.

I've got all the drivers, correct adb files, and correct twrp disc images. I rooted my brother's U11 using the same process, with the U11's files.

  • 1
    The command you have posted should not flash anything. Just boot into TWRP. What happens exactly on your phone after executing fastboot boot twrp.img?
    – Robert
    Jan 22, 2021 at 9:15
  • The above cmd should work. ask in support thread. in case fastboot boot is disabled for some reason, try this trick: 1) get current boot slot 2) flash twrp.img into boot partition (other slot) 3) switch slots + reboot 4) restore boot partition (you can mirror slots with dd via terminal) 5) install TWRP via twrp.zip into both slots (recovery ramdisk in boot) or via the "Install Recovery Ramdisk" option 6) switch slots back + reboot Note: you may lose root
    – alecxs
    Jan 22, 2021 at 10:36
  • So I've figured out, I needed a different command. I looked a bit longer, and found that .\fastboot flash recovery twrp.img actually runs it and gives feedback. my new issue is getting the "23 RU _READ_PARTITION_FAIL read/open partition fail". it's on the latest twrp img, that's dated on december 2020. Jan 25, 2021 at 23:01
  • what don't you understand in "read/open partition fail"? please read the installation instructions according to your device (linked above). 'fastboot flash recovery twrp.img' won't work because there is no recovery partition at all (as mentioned in installation instructions)
    – alecxs
    Jan 26, 2021 at 8:39

1 Answer 1


My reply from the XDA support thread was already posted here, however I will formally reply now that if you're seeing "flash images success (1/1)", then you're in Download mode. In order for the "fastboot boot" command to work, you have to be in Bootloader. There is an option to "reboot to bootloader" from the main Download mode screen. Choose that option, and then you will be in the correct mode to use the "fastboot boot" command.

You mentioned U11, however the difference with that device is that it has a recovery partition (U12+ does not), and thus the install method for it is to flash the image, not boot it. If you wanted to fastboot boot a recovery image on U11, you likewise would need to be in Bootloader mode.

  • so fastboot ins running in two different modes? by any chance you are refering to hboot? do i understand this correct this is something htc special? android.stackexchange.com/questions/13440/…
    – alecxs
    Jan 29, 2021 at 22:03
  • 1
    Yes, fastboot works both in Download and Bootloader mode. HBOOT is something else, and is only on older HTC devices. HBOOT stands for "Htc BOOTloader". Jan 30, 2021 at 23:10

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