Xiaomi Mi 11 Ultra Green Screen and reboot

[SnN Day :)]

Hi! I've checkes tons of forums, haven't found an answer for me because it's always not my case.

PROBLEM:
My Mi 11 Ultra boots up, shows a logo, a lock for 2-3 seconds (bootloader unlocked) and then blinks with green screen for a moment and instantly reboots. Also my battery is alright, it charges up. I tried to replace not one but two motherboards, didn't help. Dispay is untouched, it works perfectly in TWRP, no lag, instant response. I can access TWRP or Fastboot, it doesn't reboot and my PC sees the phone both in device manager and in fastboot.exe. However TWRP doesn't recognize the storage in my phone on PC, just like "Internal Storage" and then an empty folder I can't put anything in. Also sometimes when I charge my phone it shows an empty battery with a lightning an then shuts with consecutive reboot, but I guess that's another case that goes next. Again tested on both motherboards. When I turn the phone on and go to fastboot or recovery it gets unfathomably hot (CPU temp is like 60 degrees showed by TWRP). Tried to replace several parts that MUST work, I know that, like motherboards. Back screen is untouched.


WHAT I TRIED:
Wipe through TWRP - No effect
Recover file system through TWRP - No effect
Drying from inside with a fan - No effect
Switching card profiles A to B and doing 2 previous actions - No effect
Charging for 2 hours with 10W charger (I'm scared of how hot it gets, so 10W) - No effect
Changing File system to others and back like one thread suggests - No effect

Do you think it's a battery problem? Or MAY it be the one millionth chance of two faulty motherboards? I won't be able to find proper words that could describe the size of your hearts if you help me. Thanks in advance!

 

[Edo Yehezkel]

I had this issue, I cant tell if you having the same issue, specially when you saying you changed motherboard so I guess you tried it but who knows,
As funny as that might sound, unplug the backscreen cable (there is the flex cable connecting the proximity sensor,back screen,laser focus for the camera) just disconnect it and try to boot the phone, I had exactly same issue and when disconnecting that cable phone booted, so I just ordered a new flex cable and all was okay ;/

See details here :

Mi 11 Ultra (Bricked?) - Please help

Hi, Today's morning my Mi 11 Ultra decided to brick itself(?) and now I can't turn it on, and the phone is stuck in a boot loop. This case is hard to identify for me as this happened during watching YouTube (no updates, no interference in system files, nothing). I was just using my phone as...

xiaomi.eu

and my comment there ;-)

GL hope for the best

 

[SnN Day :)]

I had this issue, I cant tell if you having the same issue, specially when you saying you changed motherboard so I guess you tried it but who knows,
As funny as that might sound, unplug the backscreen cable (there is the flex cable connecting the proximity sensor,back screen,laser focus for the camera) just disconnect it and try to boot the phone, I had exactly same issue and when disconnecting that cable phone booted, so I just ordered a new flex cable and all was okay ;/

See details here :

Mi 11 Ultra (Bricked?) - Please help

Hi, Today's morning my Mi 11 Ultra decided to brick itself(?) and now I can't turn it on, and the phone is stuck in a boot loop. This case is hard to identify for me as this happened during watching YouTube (no updates, no interference in system files, nothing). I was just using my phone as...

xiaomi.eu

and my comment there ;-)

GL hope for the best

Thanks, I'll try
If it's a hardware issue like many people say then the only unchanged parts that under my radar are camera module and back panel. When I do "fastboot getvar all" it shows both battery and charging are alright. So the bottom of the phone must work. I'll try to replace a camera as well later and get back with the results

 

[Edo Yehezkel]

Thanks, I'll try
If it's a hardware issue like many people say then the only unchanged parts are camera module and back panel. I'll try to replace a camera as well later and get back with the results

I feel like you will experience the same as me (Hopefully for you that it is that) and that only the flex cable that going over the back panel needs to be replaced, but first see of course it's booting, gl.

 

[SnN Day :)]

I had this issue, I cant tell if you having the same issue, specially when you saying you changed motherboard so I guess you tried it but who knows,
As funny as that might sound, unplug the backscreen cable (there is the flex cable connecting the proximity sensor,back screen,laser focus for the camera) just disconnect it and try to boot the phone, I had exactly same issue and when disconnecting that cable phone booted, so I just ordered a new flex cable and all was okay ;/

See details here :

Mi 11 Ultra (Bricked?) - Please help

Hi, Today's morning my Mi 11 Ultra decided to brick itself(?) and now I can't turn it on, and the phone is stuck in a boot loop. This case is hard to identify for me as this happened during watching YouTube (no updates, no interference in system files, nothing). I was just using my phone as...

xiaomi.eu

and my comment there ;-)

GL hope for the best

Alright, as I said I returned with the results:
I disconnected the secondary screen - no effect
Changed the camera module - no effect

I genuinely don't understand where the problem is. Maybe, I need to disassemble and dry my battery from inside?! (because the battery controller is OK according to fastboot variable). Maybe when it got transported some droplets of water got inside Idk...

I guess that's it
I'll try one last time drying it out with opened sim card tray and the battery separately, but I'm pessimistic on that

 

[Edo Yehezkel]

Damm thats just crazy, I was almost sure you will fix it in the same way it was for me as it exactly the same symtom, I guess when this green flicker happen it just means something shorting, in my case it was that flex cable, I guess each phone with its issue althogh you actually changed the whole motherboard so really not sure what more ‍

 

[SnN Day :)]

Damm thats just crazy, I was almost sure you will fix it in the same way it was for me as it exactly the same symtom, I guess when this green flicker happen it just means something shorting, in my case it was that flex cable, I guess each phone with its issue althogh you actually changed the whole motherboard so really not sure what more ‍

Dude, I fixed the phone and omg I'm dead. You know what the problem was? When I was connecting the back screen cable it was touching the ultra-wide camera and creating a circuit. That's why the system responded that way! I had literally NOTHING broken lol! xD

 

[Edo Yehezkel]

Haha if thats the case I guess thats what I had too and I just thought replacing this flex cable fixed it when maybe it was okay but touching like you say,
Told you its related to this back screen cable, something really senstivite there