Lenovo Z2 Plus - Custom ROM installation

As you may already be knowing Lenovo Z2 Plus is a great phone with very good hardware, let down by the poor software. It has become more problematic after receiving the Nougat update. The Snapdragon 820 CPU it has is also present in OnePlus 3 and many of us know how that phone performs. You can’t see the same performance in Z2 Plus.

I searched and read a lot on the internet forums to know what people are doing to make it better, if at all. I found that people claim it performs much better after installing a custom ROM. Also now a days a custom ROM can be installed without ROOT, you just need a custom recovery, custom ROM and a correct procedure to follow.

Below are the posts that I referred to flash custom ROM on my Z2 Plus. I have given them in the sequence that I followed to successfully flash the custom ROM. Also I would recommend NOT to update the phone software to Nougat (ZUI 2.5.104 ST) if you plan to go for custom ROM, because the baseband included in ZUI 2.5.104 ST didn’t work really well with the DU custom ROM I installed. The older ZUI 2.0.093 baseband performs really well. But if you have already upgraded to Nougat you may still go ahead with the custom ROM process and see if it behaves better in your case. If not, then you may go back to older version by following below link:

Downgrade from Nougat, if required: https://zukfans.eu/community/threads/zuk-z2-plus-downgrade-from-2-5-104-st-to-earlier-version.6240/#post-49588. For detailed process please refer to https://zukfans.eu/community/threads/howto-flash-a-stock-zui-rom-zuk-z2-z2131-only.104/. Make sure you read it couple of times and understand before going ahead. Some of the steps are really complicated. Instead of the Chinese ROM in this forum you can install ZUI 2.0.093 as given in the first link above. Also, this is the procedure to be followed in case you brick the phone, however the procedure then becomes even more complicated as putting the bricked phone into EDL mode adds to the complication.

In these forums you’ll notice people referring to the phones as either z2131 or z2132, basically z2131 is the 32gb variant and z2132 is the 64gb variant as I read in the forums. Somewhere I also read that z2131 is the Chinese variant and z2132 is the Indian variant. But everywhere it’s also mentioned that both are the same hardware wise.

Choose a custom ROM: https://zukfans.eu/community/threads/new-z2-plus-rom-comparsion-and-review-guide-to-best-rom-choice.6029/. I selected Unofficial Dirty Unicorns.

Unlock Bootloader: https://zukfans.eu/community/threads/zuk-z2-bootloader-unlock.62/.

01. A PC with windows, I used Windows 7, not sure about other versions of windows.

02. The USB cable that came with the phone.

03. Adb/fastboot – download the Android SDK as given in the forum and install on the PC.

04. On the phone go to Settings > About Phone and then tap “ZUI version” continuously until you see a message saying “now you are a developer”.

05. Go back to Settings > Advanced Settings > Developer Options > Enable USB debugging.

06. Go to Settings > About Phone > Status and note down the serial number. It should be 6 or 7 or 8 characters long.

07. Take below steps to get the “unlock_bootloader.img” file to unlock the bootloader:

Go to https://passport.lenovomobile.com/wauthen3/wauth/jsp/register.jsp and register an account there, choose “Register via email address“.
Then use only the Internet Explorer (if you’re on Windows…) and go to http://developer.zuk.com/bootloader
DO NOT translate the page, open a second browser, where you can translate the page.
Click on the button highlighted in the picture below:

Do the required steps like enter model as Z2, enter the serial number. If the serial number is 8 digits then enter it as it is, else add one or more ‘zero’ at the end to make it 8 digits. After step 2 you are asked to log in, log in with the credentials that you provided during registration.
After successful login the “unlock_bootloader.img” file will be sent to the provided email as an attachment. Download the file to a directory on local folder.

08. Now refer to the original post at the first line of “Unlock Bootloader” section to complete rest of the steps. Basically the below:

Connect the phone to an USB port on your computer using its own cable.
Using windows explorer go the directory where the adb.exe and the unlock_bootloader.img files are located. Shift + Right Click and choose “Open Command Window Here”.
In the command window type “adb devices”, it should show a number. If it doesn’t, then see if USB driver is installed properly and adb.exe is in the current folder. Restart the PC and the phone and try again.
Once device is detected, reboot it to bootloader mode by running “adb reboot bootloader”.
Then to unlock, run “fastboot -i 0x2b4c flash unlock unlock_bootloader.img” and then “fastboot -i 0x2b4c oem unlock-go”. Warning!! this will erase the internal memory of the phone.

If you just wanted to unlock the bootloader then you just did it. If you want to install a custom recovery (TWRP) then go to the steps given below.

09. Installing Custom Recovery (TWRP): Refer to https://zukfans.eu/community/threads/recovery-official-twrp-3-1-0-for-zuk-z2-lenovo-z2-plus.5865/ and https://twrp.me/devices/zukz2.html (The official TWRP site For Z2 Plus).

You don’t need to ROOT your phone just to install custom recovery and ROM.
Download the recovery from https://dl.twrp.me/z2_plus as given in the TWRP official site, save it to the same directory as ‘adb.exe’ and ‘fastboot.exe’ and rename it to ‘twrp.img’ just for convenience.
While in the “bootloader” mode, run below commands:
fastboot -i 0x2b4c flash recovery twrp.img
fastboot -i 0x2b4c reboot

Now the phone will start to reboot; while booting up it’ll show a message to press any key for 5 seconds, press one of the volume keys. It will then go to a menu where you need to choose “Recovery” option using the volume +/- keys and press the power button to select it. Then it should go to the TWRP recovery. In case it doesn’t, reboot it again and follow the process. Once in TWRP the first question you’ll see is whether to keep it ‘read only’ or enable ‘Read Write’. It’s upto you, to be safe I kept ‘Read Only’ so that the partitions don’t get altered.

10. Custom ROM Installation: Unofficial Dirty Unicorns – https://zukfans.eu/community/threads/7-1-x-z2-unofficial-dirty-unicorns-by-davidevinavil.4279/ – this is the ROM that I chose and am very happy with. You may choose another by referring to https://zukfans.eu/community/threads/new-z2-plus-rom-comparsion-and-review-guide-to-best-rom-choice.6029/.

Download the ROM and GAPP as given in the link above.
While the device is in TWRP connect it to the PC with USB cable.
Copy the ROM and GAPPS zip files into the phone.
Disconnect the cable.
Wipe Data, Cache and Dalvik Cache
Flash ROM and GAPPS
Reboot

Enjoy…!!

Reverting to Stock ROM:

If one day you want to revert to stock ROM, then please follow the method here; it’s absolutely correct and I’ve used many times with expected results. However, I’m providing the sequence of steps below again for convenience:

a. Download Chinese ROM ZUI 1.9.044 from here. Extract to a folder and provide “ask.lenovomobile.com” as password if asked.

b. Download India ROM ZUI 2.0.093 from here. Extract to a folder and provide “ask.lenovomobile.com” as password if asked.

c. Assuming your PC has ZUK USB driver, ‘adb’ and ‘fastboot’ already installed. If not, install them and also download and install QPST from here.

d. Make sure your phone’s boot loader is unlocked. You can check that by rebooting to bootloader mode.

e. Run QFIL (the program in QPST package) on your PC.

f. Reboot EDL mode: Enable USB debugging on your phone, connect USB and issue command “adb reboot edl” from a command window on your PC.

g. Now QFIL should be able to see your phone as “QDLoader 9008” on some COM port.

h. Then follow the procedure here to flash ZUI 1.9.044. If you don’t find any “.mbn” files in the downloaded ROM directory then use the “*ddr.elf” file. Rest of the process should be as given in the link.

i. After a successful flash and the phone is rebooted into a Chinese ROM, just do some guess work, touch the “skip” option in Chinese in all initial setup screens (in top right corner). Finally again enable developer options and enable USB debugging. You’ll have to check some options before finding them, but some words like ‘USB’ and ‘ZUI’ etc. are in English and can be recognized.

j. Again do a “adb reboot edl” and flash the Indian ROM on top of the Chinese ROM. If QFIL flashing process fails then restart your PC as well and redo the process.

k. In my case after flashing the Indian ROM and a reboot and the initial configurations, it automatically detected the next update and notified me to download and install, which is 2.0.133.

Congrats, you’ve done it.

You can follow the method given in below screen shot to verify the status of your phone: