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Unlocking Bootloaders/Lenovo ZUI

From postmarketOS Wiki

Most Lenovo devices running Android ZUI require a signed file to unlock the bootloader.

Before unlocking

Warning WARNING: Read everything on this page before starting the process!
  • Backup your data, because your device will reset to factory settings, there's no way around this.
  • Update your system to the latest version, this can be done using the system updates or via the RSA tool linked bellow.
  • Go to "Settings → General settings → Developer options" and enable "OEM Unlocking".
  • Go to "Settings → About tablet → Status" and write down your "Serial number", it's needed later.

Request signed sn.img

Note ZUI.com is related to Lenovo, all Lenovo Android ZUI devices have many zui.com APKs.
  • Create a Lenovo account. The same account will be used for the Lenovo forums, support pages, RSA and ZUI.com. NOTE: One account can unlock only 3 devices per year.
  • Register the product "Serial number" in your Lenovo account.
  • Go to https://www.zui.com/iunlock - it's a website in Chinese, you can use an online translator to translate text, but use copy/paste, don't use the full-page translator.
  • Read all the text from that page, there are many notes on what to expect and how to actually perform the unlock.
  • Follow the instructions on the page. There are 4 main categories on the side. The first one is for Lenovo Mobile the last for Lenovo (WiFi-only) Tablets, there's also one section for Lenovo ZUK devices. Select one.
  • There's a Log in now link in the first line of each category, it will redirect you to a page where you need to login with a Chinese phone number, but there's also a link to Sign In with Email.
  • Fill in the form details, IMEI, SN, email, solve the captcha and accept terms and conditions.
  • Wait for your request to be processed and make sure to also check your Spam directory, not just your Inbox. You'll have to wait up to one day for your request to be processed.

Unlocking

Warning WARNING: Once unlocked, a device will no longer receive OTA updates!
Note Some devices running the ROW (Rest of World) firmware do not require a sn.img to be unlocked, skip to the last 2 steps!
  • Open the received email and download the sn.img file received. It's a link to http://cdn.zui.lenovomm.com/developer/tabletboot/ABCDEFGH/sn.img, where ABCDEFGH is the serial number of your device.
  • Reboot into fastboot mode.
  • Flash the image using fastboot flash unlock sn.img
  • Unlock using fastboot oem unlock-go. You need to quickly confirm using the volume buttons. If you get the error "Prohibit unlock operation", it's because you forgot to enable "OEM unlocking" in "Developer options".
  • Check if bootloader is now unlocked fastboot getvar unlocked

See also