Howto unlock bootloader and get TWRP on ZUK Z2 Pro

weimerd

ZUKFans Staff
Staff member
Sep 6, 2016
2,450
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t.me
#1
DISCLAIMER:
take care, this will erase all data on phone. I'm not responsible for any data loss. Follow the instructions on your own risk!



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NEW:

You updated to ZUI 3.5 using https://zukfans.eu/community/thread...t-from-zui-1-9-to-latest-zui-for-z2-pro.7851/ ? Congrats!

Once you updated to ZUI 3.5 you don't need to get unlock_bootloader.img anymore.

To activate developer option click 7 times on ZUI version under settings - system - about:
Screenshot_2018-03-26-19-34-27-1283872640.png
-
Screenshot_2018-03-26-19-34-40-0745131217.png
-
Screenshot_2018-03-26-19-34-58-0044320019.png

Once you did that you get developer options in settings - system:
Screenshot_2018-03-26-19-35-13-0366231732.png

Click on it and activate the options OEM unlocking and USB debugging
Screenshot_2018-03-26-19-36-00-0804789522.png

You can accept the following warning:
Screenshot_2018-03-26-19-35-38-1867382732.png

Now:
  1. Setup ADB and Fastboot on your PC. (can be found here as well: https://forum.xda-developers.com/showthread.php?t=2317790)

  2. Connect your Lenovo ZUK phone to the PC.
    └ If you get a prompt on phone’s screen to Allow USB debugging, tap OK.
  3. Open a command window inside the folder where you saved your adb and fastboot install (I suggest using C:\ZUK). To do this, open the folder and then “Shift + Right click” on any empty white-space inside the folder and select “Open command window here” from the context menu.

  4. Once command window is open, issue the following command to boot device into bootloader mode:
    adb reboot bootloader

  5. Once in bootloader mode, issue the following command to unlock the device:
    fastboot -i 0x2b4c oem unlock-go
    └ You’ll see the following output:
    ...
    OKAY [ 0.041s]
    finished. total time: 0.041s
  6. Now phone will reboot. Let the reboot finish completely. Then do "adb reboot bootloader" again.

  7. now flashing twrp. Download latest twrp version here: https://twrp.me/zuk/zukz2row.html
  8. Make sure the downloaded twrp version is located in adb directory as well. Rename it into twrp.img. Then in command prompt type:
    fastboot flash recovery twrp.img
    (if your device is not recognized check hardware manager for driver. You may use fastboot -i 0x2b4c flash recovery twrp.img instead)
  9. Reboot your phone to system using the following command:
    fastboot reboot

That's it. You unlocked bootloader and flashed twrp.


--------------------------------------------------------------------

OLD:

This is a backup copy of https://www.theandroidsoul.com/unlcok-bootloader-zuk-z2-pro/
All credits to https://www.theandroidsoul.com/unlcok-bootloader-zuk-z2-pro/ !
I just copied it here so everyone can find all related to ZUK here.


How to Unlock Bootloader on Lenovo ZUK Z2 and Z2 Pro
  1. On your Lenovo phone, go to Settings » About » Status information» and make a note of your device’s Serial number.

  2. On your PC, open developer.zuk.com/bootloader websiteusing Chrome browser.

  3. Once the is opened, right-click anywhere on the page and select “Translate to english” from the context menu.

  4. Read the terms & conditions and then click on the Carry on button at the bottom of the page.

  5. On the next page, select your device model from drop-down box.

  6. Next, enter your 8-digit serial number into Serial number box.
    └If you’ve a 7-digit serial number, add a zero (0) to end. If you’ve 6-digit serial number, add two zeros (00) to the end.
  7. Provide your Email ID in the EMail box. Bootloader unlock files will be sent to this E-mail ID.

  8. Tick/check-mark the the two conditions above submit button, and then hit the SUBMIT button.
    └ You’ll get a message on screen in chinese. It means, the unlock file has been sent to your E-mail ID.
  9. Open your email account, look for an e-mail from Lenovo and download the unlock_bootloader.img file from the mail.

  10. Put the unlock_bootloader.img file in a separate folder on your PC.

  11. Setup ADB and Fastboot on your PC. (can be found here as well: https://forum.xda-developers.com/showthread.php?t=2317790)

  12. Enable Developer Options, USB Debugging & OEM unlock on your device.

  13. Connect your Lenovo ZUK phone to the PC.
    └ If you get a prompt on phone’s screen to Allow USB debugging, tap OK.
  14. Open a command window inside the folder where you saved unlock_bootloader.img file in Step 10. To do this, open the folder and then “Shift + Right click” on any empty white-space inside the folder and select “Open command window here” from the context menu.

  15. Once command window is open, issue the following command to boot device into bootloader mode:
    adb reboot bootloader

  16. Once in bootloader mode, issue the following command to flash the unlock_bootloader.img file to the device:
    fastboot -i 0x2b4c flash unlock unlock_bootloader.img
    └ You will see a similar output on command window as shown in box below:

    target reported max download size of 1610612736 bytes
    sending 'unlock' (0 KB)...
    OKAY [ 0.037s]
    writing 'unlock'...
    OKAY [ 0.053s]
    finished. total time: 0.090s
  17. Once unlock_bootloader.img file is flashed successfully, issue the following command to finally unlock bootloader on your Lenovo ZUK phone:
    fastboot -i 0x2b4c oem unlock-go
    └ You’ll see the following output:

    ...
    OKAY [ 0.041s]
    finished. total time: 0.041s
  18. now flashing twrp. Download latest twrp version here: https://twrp.me/zuk/zukz2row.html
  19. Make sure the downloaded twrp version is located in adb directory as well. Rename it into twrp.img. Then in command prompt type:
    fastboot flash recovery twrp.img

  20. Reboot your phone to system using the following command:
    fastboot reboot

That's it. You unlocked bootloader and flashed twrp.


--------------------------------------------------------------------


All credits to www.theandroidsoul.com. I slightly changed the instruction with adding twrp flashing at the end and integrated an alternative link to adb/fastboot download.
 
Last edited:

Yag

New Member
Sep 11, 2017
15
2
3
#3
I'm doing something wrong...
That works:
C:\bootloader>adb reboot bootloader
adb server is out of date. killing...
* daemon started successfully *


And then it fails::
C:\bootloader>fastboot -i 0x2b4c flash unlock unlock_bootloader.img
sending 'unlock' (0 KB)...
FAILED (command write failed (No such device or address))
finished. total time: 0.005s

...but what?
(sorry for german, I was a bit confused :confused:)
 
Last edited:

weimerd

ZUKFans Staff
Staff member
Sep 6, 2016
2,450
1,172
113
t.me
#4
Ich mach schon wieder alles falsch...
Das hier ging noch:
C:\bootloader>adb reboot bootloader
adb server is out of date. killing...
* daemon started successfully *


Und dann fährt es vor die Wand:
C:\bootloader>fastboot -i 0x2b4c flash unlock unlock_bootloader.img
sending 'unlock' (0 KB)...
FAILED (command write failed (No such device or address))
finished. total time: 0.005s

...nur was?
english please ;)

send me a pm in german or make a thread in german subforum.

You need to restart your computer as adb seems not to work correctly.

Did you activate usb debugging in developer options on phone?
 

crisps

Well-Known Member
Aug 28, 2016
1,110
473
83
#5
plz keep this clean as possible....
if you have problems open thread...

if there is something wrong in tutorial or any improvements post here
 

mar.ur

Active Member
Nov 9, 2017
394
133
43
#10
I unlocked bootloader in that way on Zui 3.5.316 . I was thinking that will be a easy way to relock bootloader again . Fastboot -i 0x2b4c oem lock-go .Unfortunately there is "relocked" status in bootloader . Btw you can unlock bootloader and install twrp without any problems .
 
Last edited:
Likes: ringo

weimerd

ZUKFans Staff
Staff member
Sep 6, 2016
2,450
1,172
113
t.me
#11
There is new way to unlock bootloader on Zui 3.5.316 . In developer option select oem unlocking . Run into fastboot mode and write command in cmd - fastboot -i 0x2b4c oem unlock-go .
You don't need flash unlock_bootloader.img
finally ZUK made up a way to get rid of that unlock server stuff :)

Anyway you can lock again using ZUI 1.9.

This OEM unlock option is available since 3.5. Did not know it can be used in that way :)

Thanks, I will give it a try soon when doing next flashing tests ;)
 

siretfeL

New Member
Dec 13, 2017
2
1
3
#16
...followed your method (new), from stock rom/recovery locked bootloader ZUI 3.5.3444 (never unlocked before) and in step 6 the phone booted factory reset and lost all data...is it normal?

EDIT...never mind just find out it is normal...but please make a note for those who don't know/suspect/read this elsewhere...
 
Last edited:
Likes: nero355

weimerd

ZUKFans Staff
Staff member
Sep 6, 2016
2,450
1,172
113
t.me
#17
...followed your method (new), from stock rom/recovery locked bootloader ZUI 3.5.3444 (never unlocked before) and in step 6 the phone booted factory reset and lost all data...is it normal?

EDIT...never mind just find out it is normal...but please make a note for those who don't know/suspect/read this elsewhere...
added it again on 1st post.

But if you came from the thread this post is reffering to at the beginning there is no data on your phone anyway.

However I made it more clear now with a starting disclaimer ;)
 
Likes: nero355

siretfeL

New Member
Dec 13, 2017
2
1
3
#18
...i came from another thread (bruneba's updating to Oreo and i missed it in faq, my fault totally)...thank you for your valuable time and effort...

...just for clarification, I should mention that also I could only get TWRP with "-i 0x2b4c" added to the commands, else root recovery wouldn't change...but maybe because i used the portable version of ADB/fastboot you linked...thanks again
 
Dec 25, 2017
36
2
8
#19
Hi,

I have the ZUI updated to the 3.5 version, but I am not sure that "Once you updated to ZUI 3.5 you don't need to get unlock_bootloader.img anymore".

because when I execute "adb reboot bootloader", I have the following settings:

FastBoot mode
Product_name - QC_reference_phone
Variant - MTP eMMC
BootLoader Version -
Serial Number - 82170442
Secure boot - enabled
Device State - locked

So I assume that the fastboot is locked , and I should execute therefore fastboot -i 0x2b4c oem unlock-go , but previously make a backup of the all data, because if I unlock the bootloader it will behave like a factory reset, doesnt it?
 

MRDA

Active Member
Mar 18, 2017
395
92
28
mrda.wordpress.com
#20
OEM unlock seems to be prohibited on ZUI versions lower than 3.5. I tried the old method from 3.1.194, only to get a "oem unlock is not allowed" for my efforts. Had to install the OTA of 3.5.388 to get anywhere with that.

Also, add "Repeat developer options sequence and enable USB debugging and OEM unlock" to step 6.