Stuck in bootloop after downgrade - LG Optimus Black

Hi all
As the title states my phone appears to be stuck in a boot loop of sorts.
So I loaded the German V20N via KDZ updater last week and that worked perfectly.
I decided I wanted to use Zeus v2.1 by Huexxx, but I needed a rooted device for this.
So I put the phone into update mode by pressing vol+ and power button.
I then used KDZ updater once again using V10B. This also appeared to update fine.
However when the phone finally booted up I got many many errors of:
"process system root is not responding".
I tried to force close them but to no avail, so I removed the battery.
I powered the phone on yet again and then it shows the LG logo then reboots possibly a few times.
After that it eventually lands up showing the Unlock screen but the touch keys at the bottom are flashing. It will then reboot again and do the same thing.
I tried removing the battery pressing vol+ and power and then plugging it into the USB to get the software update mode. However the phone just turns on instead of showing the update screen.
I have also tried pressing vol- and power. It also just appears to turn the phone on.
Other errors received are:
"The process android.process.acore has stopped unexpectedly. Please try again"
The errors pop up and and eventually the phone will hang and restart before I can actually do anything on it.
The computer doesn't seem to pick up anything when it's plugged into the USB either

http://forum.xda-developers.com/showthread.php?t=1448803

I did see that thread, but I was under the impression that because I could not get to the software update mode that it wouldn't work.
As it turns out... You must not press vol+ and power when plugging into usb. Just the vol+ key.
Will let you know if it works via SmartFlashTool.
Thanks

Feel rather silly now...
It seems to be working!
Hopefully I will not screw it up again.

Related

[q] [help] moto milestone bootloop at android logo

I have a Motorola milestone (second hand) and tried to load a update for it then i noticed the following problems:
- boot looping at the android logo
-when i tried going into bootloader i get a blank black screen
-when i go into recovery and try to update using "update.zip" i get a EOCD error and another time i get a authorization error
WHAT TO DO????
Come on dude,
Just search EOCD error, I think you will find at least 15 topics.
You lost root, Nedd to flash vulnerable recovery sbf. You will find latest instructions on nadalbak site.
You can find site inside his cm7 topic. Milestone android development.
Sent from my Milestone using xda premium
i'm fairly new to the milestone side, the version that is on the phone is 2.2
Everybody's instruction is to put the phone in bootloader mode and connect to the pc but i only get a black screen and then the phone restarts hence rsd lite not picking it up
Put it in recovery and try to flash another sbf, it should work.
Trough rsd lite.
try that just now and still no response on the pc, and i know the usb port is working because i charged the phone
Are you sure your drivers for phone are correctly installed?
Explain correctly installed?
yeah so what about when i try going into boot loader and get a blank screen?
In the early development of moto driver's phone wasn't recognised by rsd lite.
I didn't hear of that problem anymore though. The solution was to reinstall / install drivers again or try on another pc.
Cable could also be a problem.
Are you trying to enter bootloader with the cable connected to phone? If yes try without and after connect it.
The cable isnt the problem, im sure of that and i tried on two other laptops but they are 64 bit windows 7 but anyways why when i press "power+vol up + camera" i only get a black screen and not black screen with other milestones?
I'm thinking thats the problem or reason why rsd lite not picking up the phone cuz its not in bootloader mode
Ahhh
It took some time since last used bootloader.
But I think is power + x for bootloader.
==== update ====
my bad that's for recovery
oky just tested:
it's power + up key from keyboard
now when i first pressed the power i got a black screen, so i pressed the power again while holding the up key .. and voila:
bootloader 90.78
battery ok
....
good luck ..
when this happened to me i was shocked so much , but then i got it fixed so yay
sigh was trying that from lastnight but no luck
Does anybody have a video to how this done because i'm wondering if i'm doing it right cuz i'm still getting black screen when trying to go into bootloader, i pressed "power + up button on DPAD" and then pressed the power button again but still black screen
While the phone is off, hold the up button on the D-pad and press the power button. Do not let go of the up button until the bootloader screen comes up.
while the phone is off? i can't turn off the phone because its just looping so i take out the battery then put it in and press up and power button so is that the right way?
Yes,
If it doesn't work, for pre 90.78 bootloader I think it was another combination of keys.
Google it
Got it all wrong, the problem was that a app was installed and then the phone was restarted then the looping start at the android sign
no luck, the ways i see is the same as urs
reesieBennett said:
Got it all wrong, the problem was that a app was installed and then the phone was restarted then the looping start at the android sign
no luck, the ways i see is the same as urs
Click to expand...
Click to collapse
about the video:
found this on youtube:
bootloader:
http://www.youtube.com/watch?v=xjQcvg3Eplc
recovery:
http://www.youtube.com/watch?v=H3Vl9NbU6Ag&feature=related
if you enter recovery try wiping everything / factory reset and see if it get into android.
other than this i haven't got any other idea,
it is possible to reboot it with adb if you got a rom that supports adb at boot. ex CM7. cm6 and froyo rom not sure but this is a long shot.

Error message when starting

was with the original rom lg. and then went instalr the recovery of the cyanogen rom manager app, and then hung up the phone and now the message appears in red at the top of the screen
"Critical Failure: Unable to start Kernel.
Unrecoverable bootloader error (0x00000002)"
and I can not get into download mode to install the original rom again.
and now what do I do? I lost my phone?
you flashed cwm without unlocking your bootloader. re-flash latest jellybean kdz file for your phone using http://forum.xda-developers.com/showthread.php?t=2069723, then read some more about unlocking bootloader, and then start again.
Flying_Bear said:
you flashed cwm without unlocking your bootloader. re-flash latest jellybean kdz file for your phone using http://forum.xda-developers.com/showthread.php?t=2069723, then read some more about unlocking bootloader, and then start again.
Click to expand...
Click to collapse
but now I am unable to get into download mode on the phone. is
" Now just hold down vol - key ( hold hold hold dont release !!!! ) and plug the USB cable until you get screen like this :-"
he does not. whenever I do this it only vibrates strong and goes to the screen with the error message. I do not know why that. remember one time it happened to me already but can not remember how I resolved it is possible to even lose the download mode?
Its not possible afaik. Are you sure you are holding only vol - key and plugging in? Dont hold power key!
yes, I'm almost the whole day trying to get into download mode by pressing volume down + connecting the usb. and whenever it vibrates strong and hangs on lg logo. tried to volume up + usb connect. and no download mode. I'm going crazy with this phone. otherwise hesitate to hard reset? or other shortcut to download mode?
Rafael20. said:
yes, I'm almost the whole day trying to get into download mode by pressing volume down + connecting the usb. and whenever it vibrates strong and hangs on lg logo. tried to volume up + usb connect. and no download mode. I'm going crazy with this phone. otherwise hesitate to hard reset? or other shortcut to download mode?
Click to expand...
Click to collapse
hard reset wont help you, as far as i know, you somehow need to enter s/w upgrade screen. did you try it with battery out?
he battery of the same error, and no battery it does nothing, or vibrate, or flash screen, nothing happens
Will I not be able to see my optimus running again? :crying:
it is not possible to load the kernel, what could I do?
Critical Failure: Unable to start Kernel. Unrecoverable bootloader error (0x00000002)
Rafael20. said:
it is not possible to load the kernel, what could I do?
Click to expand...
Click to collapse
Hi Raphael20 and everyone else,
Did you manage to figure out a solution to this? I have the same issue, i.e. cannot start my phone by holding the power button. Not even when people suggest to get to the S/W Update screen by holding the Volume down + plug into the computer.
I got to this error when I tried to do a factory reset. I installed the ClockworkMod Recovery. Then the factory reset via Volume up + Power button gave me the "Critical Failure: Unable to start Kernel" error. I somehow managed to get access to my phone by holding the Volume down + plug into the computer. Then tried to do a factory reset via the system settings of my phone. My phone restarted and then gave me the "Critical Failure: Unable to start Kernel" screen of death! Now Volume down + plug into the computer gives me the "Critical Failure: Unable to start Kernel", no matter whether I have restarted my computer and I have tried another computer. It seems that the bootloader is wrecked.
Does anyone have any suggestions?
Thanks!

bootloop android logo

I have problem I formatted my phone via recovery and no system found. My phone going to bootloop after power on Every time i power ON the device it gets to the screen that says "Powered by android" device untrusted and keeps rebooting. Many buttons combos not working. only way to turn device off is battery disconnect. Help
mati5000 said:
I have problem I formatted my phone via recovery and no system found. My phone going to bootloop after power on Every time i power ON the device it gets to the screen that says "Powered by android" device untrusted and keeps rebooting. Many buttons combos not working. only way to turn device off is battery disconnect. Help
Click to expand...
Click to collapse
Only you can do is to flash original firware with NOST flasher.
OK i get this software but i cannot get this phone to download mode and phone has only bootloader unlocked not critical. What i can do?
OK i successfully boot my phone to download mode and all fixed. Thread closed

Could not do normal boot. Invalid KERNEL LENGTH.

This message I get when I try to power up my Note 9 N960F/DS.
I got it this way: Been running the same ROM for 2 years. Time to upgrade. Upgraded TWRP via the app. After downloading the ROM image to SD card, I tapped an app called Reboot, with the Recovery option. I suspect this app is from some old installation, and ended up on this unit via data restore. Now all I get is this message on a black screen. No logo, nothing. Message flashes once. If I plug into PC, message flashes repeatedly. Cannot boot to recovery using Vol-+Pwr, Vol++Pwr ineffective.
I suspect I bricked the phone, but I seem to remember once breaking out of this 2 years back, I think. Any ideas, clues, anything?
Try this, power off phone. Press volume up and bixby button and while pressing buttons insert data cable, phone should go to downlaod mode. OPen odin and flash stock firmware.
OK, tried it, display showed the same message until I released the buttons, then flashed the message every 4 seconds until disconnected.
OK, got it into download mode, reflashed twrp, now it's in a boot loop. Will continue working this.
It took a few tries, but I not only got everything working, I restored my data backup and upgraded to Android 10. Thanks all!
Munawar Mehmood said:
Try this, power off phone. Press volume up and bixby button and while pressing buttons insert data cable, phone should go to downlaod mode. OPen odin and flash stock firmware.
Click to expand...
Click to collapse
Thanks so much for this,you saved me.
hello, how about if my buttons arent working?
please help
tristemono said:
OK, got it into download mode, reflashed twrp, now it's in a boot loop. Will continue working this.
Click to expand...
Click to collapse
HOW DID YOU DO THIS, I HAVE THE EXACT SAME ISSUE AND AFTER HOURS OF SEARCHING YOU'RE THE ONLY OTHER PERSON WHO'S HAD THIS ISSSUE. PLEASE HELP, I CANNOT GET INTO DOWNLOAD MODE NO MATTER WHAT I DO

Weird bootloop that I've never seen before

Some months ago I dropped my phone at ocean and after stopped work because the USB part was broken. Last week I found an assistance with this part to replace and then my Xiaomi back to work normally.
I reset today and start using normally, but suddenly it stops worked with a boot loop, I couldn't use fastboot or recovery mode because the boot loop didn't stop at all, even with no battery the loop still occurring.
Your browser is not able to display this video.
Anyone knows what to do?
Connect the device to pc and run fastboot devices
While its saying waiting for devices
Hold power and vol down till the pc catches the bootloader.
Maybe it will stop the looping.
Kenora_I said:
Connect the device to pc and run fastboot devices
While its saying waiting for devices
Hold power and vol down till the pc catches the bootloader.
Maybe it will stop the looping.
Click to expand...
Click to collapse
Hello, I tried but no success because the loop stop everything I try to do.
I can access the recovery mode, but can't select any option because it reboots again. It's like rebooting every 5 seconds. Tried 'fastboot devices' but didn't show waiting for devices, then I tried 'fastboot getvar all' and worked to show the message besides couldn't stop the loop.
Thanks for your help, I'll keep trying.
Fixed guys!!!!!
The problem was in the power button malfunction, the device was loop restarting because the power button was in some way pressed. I opened, removed and installed the button again and worked =D
valhalla_project said:
Fixed guys!!!!!
The problem was in the power button malfunction, the device was loop restarting because the power button was in some way pressed. I opened, removed and installed the button again and worked =D
Click to expand...
Click to collapse
Thats great!
valhalla_project said:
Hello, I tried but no success because the loop stop everything I try to do.
I can access the recovery mode, but can't select any option because it reboots again. It's like rebooting every 5 seconds. Tried 'fastboot devices' but didn't show waiting for devices, then I tried 'fastboot getvar all' and worked to show the message besides couldn't stop the loop.
Thanks for your help, I'll keep trying.
Click to expand...
Click to collapse
same problem here . stuck in that weird bootloop. Bootloop stops some times after i used password to unlock device restarted once again.
valhalla_project said:
Fixed guys!!!!!
The problem was in the power button malfunction, the device was loop restarting because the power button was in some way pressed. I opened, removed and installed the button again and worked =D
Click to expand...
Click to collapse
how did you open can you tell
He opened the back of the phone, their might be a tutorial on the web.

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