Help with Qin F21 Pro not booting

Operating Systems Android
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1

Hello,

I recently was asked to help remove the password from a qin, because he was locked out. Since theres no recovery or way to factory reset from the lock screen, I used mtkclient to delete userdata. Turns out the filter was an mdm that was deleted so now the qin was unfiltered.

So he asked me to put TripleU MDM on it, and I did so (btw: works great, thanks @TripleU ) but I had tested some things to make sure the device works, such as signing into a google account and installing a few apps. To give it to him clean, I went to the settings app and factory reset.

When the device turned off and back on, it stopped at the initial duoqin boot logo - pre animation - and will not go past that point. I have no idea what happened, I had turned it off and back on before with TripleU MDM on there, it worked fine, but now im stuck.

I tried to clear userdata again, but didnt work either. As I said theres no recovery and to be honest, I’m totally out of my league here. If anyone can help or give advice, it would be greatly appreciated.

TL;DR - My qin is stuck at the boot logo after clearing userdata, installing tripleu mdm and factory resetting.

Thank you to @ars18 for giving me advice. Any help is appreciated.

P.S. I heard theres different versions of the phone, I dont know anything about it, if anyone can let me know how to check (without booting up obviously) please do so. The manufacturer sticker is still on back so that might help:

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UPDATE:

I followed @flipphoneguy 's advice, and unlocked bootloader and flashed an empty vbmeta, and now its bootlooping - turning off and back on again.

2

hard to know. you can try a full flash - if your near the queens new york area i can help you more

3

Nope not near there. Shouldn’t I be worried about deleting imei and nvram or something? Idk anything about that stuff

4

You can flash full as you have the IMEI because of label on the back
If you need help in the Lakewood area I can help

5

You’ll have to reflash. I don’t know exactly what filter it was but it seems like factory data reset put back stock firmware or whatever system img was saved in recovery and that wasn’t signed or something like that. You can try to unlock bootloader with mtkclient and flash just empty vbmeta. That might fix it.

@Nooch does what I’m saying make any sense?

6

Oh you think it’s abv acting up? There was no error but could be they modded lk.img
Gonna do what you said. But if I unlock bootloader why do also need to flash an empty vbmeta?

7

If you unlock the bootloader would it be the reason why you would need a empty vbmeta because unlocking the bootloader would trigger AVB

8

Someone said something about a blue or red charging port rim for new and old version

9

It’s probably the old version based on the serial number

10

Okay, I unlocked the bootloader and am flashing emtpy vbmetas rn. Fingers crossed :crossed_fingers:

11

Okay, it didnt work - but it did change something because now its bootlooping (showing initial logo and turning off and back on again)

Next step should be to flash a stock super, because maybe that got corrupted, right?
@ars18

12

I don’t know what version you have

13

Me neither.

Is it weird that im flashing a super thats 3 gb instead of the one on there thats 4?

14

Is the one on there the stock one? If yes it sounds like you’re flashing the wrong one.

15

Yes it is. Well I made a backup so worst comes to worst I’ll put it back on. Not that it boots anyway lol

16

Same error. Just bootloops again.

Now I’ll try flashing everything. Wish me luck

17

Are you able to flash stock using Format download ?

18

I’ve had similar in the past. Flashing stock boot helped. Rooted boot didn’t.

Needed to flash stock boot, patch with magisk and then reflash.

I don’t understand why I needed a reflash of the boot, but that’s what worked for me :man_shrugging:.

19

Using mtkclient. Dunno how that translates from SP Flash Tool. Is SP even available for linux?

Those seem contradictory to me. Which one worked: The stock or the root?

20

I dont know what I did but now it seems both SP Flash Tool and mtkclient wont connect to the preloader. I think it may be bricked. RIP :headstone: