[Blade Android Development] sbpetrack:
Detail on the "Enable Unlocking" bootloader that can't be unlocked

Although it is hard to understand the poster's original question because the entire post is a single run-on sentence, his question is VERY sound IMHO -- I have the identical problem and I'm at wits' end:

My phone is a Rook from EE (UK), which I understand is a carrier-branded ZTE Blade 3 A410. (I post below the output of fastboot getvar all). I apologize that I don't know what it means "to check if the phone is MediaTek" --please explain and I'll be happy to. check.

Unlike the earlier poster's phone, this one DOES have an "OEM Unlocking/Allow the bootloader to be unlocked" toggle in developer's options. The entire process of unlocking the bootloader goes completely without incident, up to the point when i need to use Volume Up or Down to cancel or confirm the unlock (and then press the power button to do the unlock):

------------------dos cmd window snippet------------------------

C:\Users\seth\Documents\My Installation Files>adb devices -l

List of devices attached

0123456789ABCDEF device product:P635E40_EE model:Rook_from_EE device:P635E40

C:\Users\seth\Documents\My Installation Files>adb reboot bootloader

C:\Users\seth\Documents\My Installation Files>fastboot oem unlock

...

---------------------------------------------end of DOS cmd snippet----------------------

PLEASE now look at the attachments to this post-- each one is a picture of the screen at some point during the bootloader-unlock process. (The blanked-out squares in the pics did not excise any text or other information; the pics were only edited to remove annoying glare from lights in the room).

The first attachment is a pic of the fastboot-mode screen. I don't know if it's strange or not that this screen is VERY simple, a single line of text. I see from various pics in this forum that usually the fastboot screen has a logo and some information. Not sure this matters, but just in case....

The second attachment to this post is a pic of the disclaimer screen.

You will see that it is the usual disclaimer screen, ending in the Yes/No choice that one is supposed to do with Volume UP/Down.

BUT NOTE: Neither line is highlighted. There is just two lines of text which say "yes" or "no".

If, at this point, I press Volume Down, the screen displays a new line for a few seconds. You can see this new extra line in the third attachment to this post. Since we pressed Volume Down, it's no surprise that the new line says that we'll be returned to fastboot. And indeed, a few seconds later, the screen switches to the screen, a pic of which is in the 4th and final attachment here.

Of course, we WANT to unlock the bootloader, so I press Volume UP and not Volume Down at this point. But When I press Volume UP -- NOTHING happens. No change at all. If I press volume Up and then press the power button, NOTHING happens.

So that's the problem: I Cant highlight the "yes" choice by pressing volume Up. I can't highlight "no" via volume Down either, but at least when I press volume down, it acts as a cancel button.

[Now that i think of it, the usual explanations all say that one has to use the volume keys to select and then press the power button. The text in the attachment doesn't mention the power button. is it possible that with this new phone, the bootloader changed and gives no feedback if one presses Volume UP -- you just have to wait a while and then it will be unlocked? I'll try that and report if that leads anywhere.]

(I'm not sure it's relevant, but just in case it is: if i press Volume UP, and then press AND HOLD the power button for several seconds, then the phone boots normally, in the DOS cmd window, the fastboot oem unlock command returns with one of two errors. I' tried it several times and always got one of two errors (exactly which one I got seemed to be random) -- either FAILED with a "read error -- unknown error" or FAILED with a "read error -- too many links")

The bottom line question is: WHAT DO I HAVE TO DO to be able to use Volume UP/Down and Power to highlight the choice I want -- namely "Yes, unlock" -- and then execute it? Or is there some other way to unlock the bootloader.

with thanks,

scott

P.S. BTW, I tried all these steps a second time after setting the phone to factory reset manually. Same exact results.

P.P.S.: And just in case it helps, here is the output of fastboot getvar all:

C:\Users\seth\Documents\My Installation Files>fastboot getvar all

(bootloader) max-download-size: 0x8000000

(bootloader) partition-size:flashinfo: 1000000

(bootloader) partition-type:flashinfo: raw data

(bootloader) partition-size:userdata: 32000000

(bootloader) partition-type:userdata: ext4

(bootloader) partition-size:cache: c800000

(bootloader) partition-type:cache: ext4

(bootloader) partition-size:system: 96000000

(bootloader) partition-type:system: ext4

(bootloader) partition-size:metadata: 2480000

(bootloader) partition-type:metadata: raw data

(bootloader) partition-size:nvdata: 2000000

(bootloader) partition-type:nvdata: ext4

(bootloader) partition-size:frp: 100000

(bootloader) partition-type:frp: raw data

(bootloader) partition-size:tee2: 500000

(bootloader) partition-type:tee2: raw data

(bootloader) partition-size:tee1: 500000

(bootloader) partition-type:tee1: raw data

(bootloader) partition-size:keystore: 800000

(bootloader) partition-type:keystore: raw data

(bootloader) partition-size:secro: 600000

(bootloader) partition-type:secro: raw data

(bootloader) partition-size:oemkeystore: 200000

(bootloader) partition-type:oemkeystore: raw data

(bootloader) partition-size:ztecfg: 80000

(bootloader) partition-type:ztecfg: raw data

(bootloader) partition-size:seccfg: 80000

(bootloader) partition-type:seccfg: raw data

(bootloader) partition-size:expdb: a00000

(bootloader) partition-type:expdb: raw data

(bootloader) partition-size:logo: 800000

(bootloader) partition-type:logo: raw data

(bootloader) partition-size:recovery: 1000000

(bootloader) partition-type:recovery: raw data

(bootloader) partition-size:boot: 1000000

(bootloader) partition-type:boot: raw data

(bootloader) partition-size:para: 80000

(bootloader) partition-type:para: raw data

(bootloader) partition-size:lk: 80000

(bootloader) partition-type:lk: raw data

(bootloader) partition-size:protect2: a00000

(bootloader) partition-type:protect2: ext4

(bootloader) partition-size:protect1: a00000

(bootloader) partition-type:protect1: ext4

(bootloader) partition-size:nvram: 500000

(bootloader) partition-type:nvram: raw data

(bootloader) partition-size:proinfo: 300000

(bootloader) partition-type:proinfo: raw data

(bootloader) partition-size:preloader: 40000

(bootloader) partition-type:preloader: raw data

(bootloader) off-mode-charge: 1

(bootloader) warranty: yes

(bootloader) unlocked: no

(bootloader) secure: yes

(bootloader) kernel: lk

(bootloader) product: ZTESH6735M_64_L

(bootloader) version: 0.5

all: Done!!

finished. total time: 0.077s