[Android Q&A, Help & Troubleshooting] DK.log:
Hi.

I wanted to install S119 (multilanguage stock without chinese apk and with pre-installed root account) in my phone. I planned to do it using custom recovery (CWM or Clarive), so I could backup my original rom before I install new one (I've done that with my earlier phones and itallways worked).

As you know, to change my recovery I need root privilages (and then I can use e.g. MTK tolls).

But here is the problem. I tried many apps to root my phone (apps for android and apps for pc):

- FramRoot - Boromir and other exploits didn't work

- OneClickRoot - zero effect (I think this app lef some malware on my PC)

- vRoot / iRoot - cant find any free download (everywhere tehy want fish my phone nb.)

- rootGenius - after few minutes of work gives a failure message

- rootAllDevices (HEXAMOB) from Play Store - zero effect

- baidu root - .apk gives a failure message, .exe cant find free download

- KingoRoot

After connect with device, aplication work a few minutes and gives me SUCCESFULL message. I have a new app SuperUser in my android. After I install and open MobileUncle MTK Tools, SuperUser ask me for root privilages to MTK (I choose Allow). After that MTK dont respond: under app header insted menu I see black screen. When I nistall and open MTK before try to root, the app work properly (but didn't have privilages to change rocovery). So I insttaled RootChecker. Rootchecker shows I don't have root privilages. So i rebooted phone. After reboot SuperUser show:

"Warrning: the Kingo SuperUser must be updated or reinstalled. Please find Kingo Root at website and install SU Binary by rooting your device again. If you have rooted your device and still see this window it is coused by locked bootloader. That lock prevent your device from being permamently rooted using internal memory write protection. Important files, such as: su binary & superuser.apk, will be removed by rebooting. You need unlock your bootloader first.".

I tried every rooting apps a several times. Between attempts I restored factory settings using that option from system menu and using option "whipe MMC" in oryginal chinese recovery.

I was wondering to use "SP Flash tool" (or similar) to flash rom S119 (with pre-installed root), and then change recovery.

But in this case I will not have a original rom backup and if something goes wrong I brick my phone :/

So, I have a 4 questions (one good answer should be enough to help me :D ):

1. How to make installed rom backup without root privilages?

2. How to root my Lenovo A850+ (tested and working way)?

3. Does anyone have a current link to free download vRoot?

4. How can I unlock my bootloader?

Please help me.

============================================================================================

Few hours later...

I tried unlock bootloader using adb and fastboot.

I connected phone to pc.

I opened command line (cmd) and type

adb devices

Console see the device (id and state "device")

I make backup

adb backup -all

Attempt unlock bootloader - way 1

adb reboot oem-unlock

Phone rebooted but not in to fastboot mode as should - started normaly (bootloader not unlocked).

I cant start phone i fastboot mode using any cobination of keys/buttons.

I started phone using

adb reboot bootloader

I see black screen and prompt

=> FASTBOOT mode...

Attempt unlock bootloader - way 2

fastboot oem unlock

Phone displays meassage about void the warranty. I agree pressing Vol+. Console displays

...
(bootloader) start unlock flow
FAILED (remote: Unlock failed - Err:0x7000)
finished. total time: 4.770s

Bootloader not anlocked :(

I search error code in google and i find youtube movie about similar problem in Sony Experia series. in that case help command

fastboot -i 0x0fce oem unlock 0xB422BA417C175FB3

In my case don't work :(

Despite all of that I decided to try change my recovery to custom (phone still in fastboot mode)

fastboot flash recovery Clariva.img

and error

sending 'recovery' (6144 KB)...
OKAY [ 0.177s]
writing 'recovery' ...
FAILED (remote: partition 'recovery' not support flash)
finished. total time: 0.190s

Any ideas?

I starting to give up :(

==================================================================

I was thinking... Maybe I can flash new bootloader? But how can I do that and would it help?

In theory I can use

fastboot flash bootloader bootloader.img

but wher can I find bootloader.img?

Besides bootloader partition can also be write-protect.

ehhh... help :D