[Q] Bootloop after low-battery auto-shutdown - Nexus 7 Q&A, Help & Troubleshooting

Hey guys,
So my N7 had gone into this auto-shutdown phase before. But in the past I always managed to fix it. This time however it's different. I get stuck in bootloop.
I've left it on charge for about 1hour+, still bootloop. Reflashed ROM, still bootloop. I'm hoping I don't need to full wipe or restore the factory image to solve it, so I'm hoping there is another solution.
Thanks.

Poor Man's TiBu after bootloop occurs
TU;DBR (Toolkit Users Don't Bother Reading)
Bootloops are generally caused by stuff that lives in the /data partition, not in the /system partition.
So, if you did a dirty flash of the ROM that won't change anything.
If your /data filesystem is healthy (can be mounted by the recovery), make a nandroid backup using TWRP and pull it off the tablet.
The TWRP <partition>.ext.win backup files are just .tar images, so there is always the possibility of recovering your market apps & data with a little bit or learning and effort on your part. But no kidding, it's not for the faint of heart. The basic outline of the idea is to:
- nandroid & get copy off tablet for safety sake
- manually delete everything in /data excepting /data/media, /data/app, and /data/data
- go in to /data/data and manually delete all folders not associated with your market apps ( stuff like com.android.* or com.google.*)
- go into /data/app and delete any .apks which are updates to system apps (gmail, etc) [*1]
- nandroid backup again - call this "nandroid2"
- boot OS and configure minimally.
- boot back into TWRP
- (manually using tar? [**2]) restore the TWRP data backup (data.ext.win) without wiping
- perform "fix permissions" in TWRP
- boot up and profit
Note that "manually" here means using the command line (via adb shell to custom recovery).
If something goes wrong with this procedure, you can always restore the first nandroid backup (the bootlooping condition) and iterate until you get things right. (That right there shows you what freedoms you get by making backups.)
If you read this far you can see that what this process does is very similar to what TiBu does - except you are doing it *after* a boot loop has occurred.
[*1] optional - might not be needed
[**2] it might be possible to just "dirty flash" the data partition from the "nandroid2" backup rather than futzing around with tar at the command line. The reason I wrote this step as shown above is because I wasn't sure if a nandroid restore to /data automatically does a factory reset of /data or whether it will allow "dirty overwrites". Note also that TWRP allows you to selectively backup/restore partitions, so you don't need to involve /system or the boot partition in any of this.
good luck

Related

[Q] re-enable OTA updates Nexus 7

Hi all,
I have a nexus 7 running Android 4.1.2 stock w/ root. Some months ago, I disabled the OTA update notification - but I can't seem to remember how!
I want to now re-enable OTA updates so that I can update to the latest android version, and not lose my installed apps.
I've searched the device for FOTAKill.apk inside /system/app, and its not found
I've also searched for frozen / hidden apps using Titanium Backup Pro... nothing
When I enter Settings -> About Tablet -> System Updates... it says I'm up to date... but I'm not, considering I'm running 4.1.2.
Any help or pointers in re-enabling OTA is appreciated!!
- make a full nandroid backup.
- using fastboot, flash the system.img file from the 4.2.2 factory image to the system partition.
- using your custom recovery, reflash a SuperSU root kit bundle.
- using the custom recovery, wipe cache and dalvik-cache.
If you don't like the result, restore the nandroid backup and proceed in a different fashion. It will probably break things like stickmount and any other changes that you caused in /system.
Note the above method is for use by lazy and sloppy users. A better approach is to make TiBu backups of only your market apps, bite the bullet, and start from scratch with a flash & (new) configuration of a pure stock ROM. In any case, every conceivable procedure should start with making a full nandroid backup and getting it copied to a safe place off the tablet.
I will also say that unless odd problems crop up, the portions of the factory install procedure (using fastboot) that deal with erasure or flashing of the userdata partition should be skipped, as these steps completely wipe your /data storage - including your /sdcard area in /data/media/0 and any CWM/TWRP nandroid backups!
It's not really clear why these steps would be needed unless the /data ext4 filesystem in the userdata partition got corrupted somehow. A more sly approach would be to use the custom recovery's "factory reset" procedure to clean up /data - either before or after flashing the factory ROM - and completely skip anything that touches the userdata partition in the factory install instructions.
good luck

[GUIDE] How to back up your ZenFone

WHY THIS GUIDE?:
As users try out different ROM's, or otherwise back up their devices for the purposes of (if it comes to that) restoring them at a later time, it is important to have a proper backup. A lot of it is common sense, but there is a quirk that is buried in the TWRP thread that if not followed could provide headaches, and a factory reset, in the long run.
BACKGROUND:
As CM 12.1 has been released, I have been trying my hand at building CarbonROM. I had two successful builds at that point, but neither get to to the setup screen (first stuck at "Starting apps", the other, froze at the splash screen). Naturally, I would want to go back to SuperZen using my backup-of-the-day. The first time I restored, the system started up fine, but something funny was happening. I couldn't get the SIM card to detect. Looking around online, I found that the only way around it is to factory reset, then take the time to set everything back up (I didn't TiBu, so that made the process even longer).
After explaining the problem to @TheSSJ, he opened up some more backup options in TWRP so the next time I tried my ROM, I did a little trial-and-error to know which partition was needed to restore and thus what needs to be backed up at least.
THE HOWTO:
First, you need TheSSJ's TWRP v20 or higher. (I never tried this with official TWRP, maybe someone can let me know if it has the same backup options?)
Reboot to TWRP. This can be done a few ways:
From ADB shell or Terminal Emulator, gain SU and type "reboot recovery" (without the quotes).
Select Reboot form the power menu. When the screen goes black, hold down Vol-Up until you get to fastboot mode. From there, press Vol-Dn twice (until "Recovery" is displayed), and press the Power button.
Use an app or Xposed module to do this for you.
Once in TWRP, select Backup. You will be presented with nine or so backup options:
Boot
Cache
config
Data
Misc
Recovery
Splashscreen
System
System Image
A minimal, effective backup should consist of:
Boot
config
Data
System
...but you can select as many partitions as you like. Cache is a good idea as well, and is typical in a backup. Remember, when you restore, you can pick and choose which partitions you want.
Personally, I back up everything but System Image and restore all of what was backed up except recovery.
Set the Backup Name, to something friendly (if desired) and change the backup destination to MicroSD (hope you got one, especially if you have one of the 16GB models).
When ready, swipe to backup. That's all there is to it!
CREDITS:
I would like to thank TheSSJ for all his hard work bringing over TWRP to our device and troubleshooting when things don't work as expected.

TWRP sayd system not mounted, then rebooted during restore, phone is softbricked

I was bootloader unlocked, latest TWRP installed, systemless root with SuperSU 2.6, cataclysm rom, ex kernel, layers, xposed. I had made a ton of backups and even kept some of them backed up in another locations. I needed to restore a backup in TWRP. At first it wouldn't let me, kept saying that phone system was mounted as read only.
this is my question #1 - How do you mount system for read in TWRP? I see there's an option called "mount," I go in there, i see settings I can select, but I don't see any option to "execute" or "apply" settings (like TWRP has on other screens - swipe to backup, swipe to restore, etc). There's no "clicke here to mount option." what do you do here?
#2 - it finally mounted rw, i think, but after picking my latest backup, it started and then when it got to 19% it reboot the phone. Phone is softbricked.
#3 - I'm very confused about all the checkboxes to restore, and all the checkboxes to wipe.
What should I be wiping and what should I be restoring? When making backups I checked all the boxes.
I had the galaxy nexus before and I knew that phone and clockworck mod inside out. TWRP is confusing and glitchy to me. I'm stuck and work with a phone without an OS and I'm starting to freak out, and don't have A to C cables with me.
Please explain where I went wrong here and how to do things correctly. I want to understand what I'm doing better, not just follow steps.
When you restored, with all the check boxes did you click "system image" for restore?
You should wipe then restore only system, data, and boot.
dontbeweakvato said:
When you restored, with all the check boxes did you click "system image" for restore?
You should wipe then restore only system, data, and boot.
Click to expand...
Click to collapse
Yes, I selected all the boxes, including system image I believe.
I did a wipe. I selected all the boxes. Went back into TWRP and now all my backups are gone. I said reboot, and TWRP said there's no OS installed. I think I deleted everything. I should not have wiped. I do have a backup saved on a computer, it's a folder with lots of .img files inside. How can I get that onto my phone with only having fastboot and TWRP modes available? I mean how can I place it on the phone in a way that TWRP would recognize it and restore from it.
I ended up just flashing the stock google image and that at least gave me a working phone back.
Yes. You beat me to it, that's what I was going to say. You have to reflash. Just remember for future references you only need to backup boot, system, and data( and efs etc). But Not "system image" that'll Bork your stuff up.
dontbeweakvato said:
Yes. You beat me to it, that's what I was going to say. You have to reflash. Just remember for future references you only need to backup boot, system, and data( and efs etc). But Not "system image" that'll Bork your stuff up.
Click to expand...
Click to collapse
I'd like to really understand this better. Do you know why system image borks the phone? Also, when you say efs etc., do you mean "absolutely everything except system image"? (I actually didn't see EFS listed there)
Well boot system and data. But you also need efs cause thats your imei. So just look around and familiarize with what youve found so far. Right now Im trying to flash 6.0.1 with a systemless root. Its kinda goin ridiculous right now because there aren't any directions or suggestions.
If you get to "no OS installed" restoring system image, then system will get you back
Sent from my Nexus 6P using Tapatalk
zgroten said:
If you get to "no OS installed" restoring system image, then system will get you back
Sent from my Nexus 6P using Tapatalk
Click to expand...
Click to collapse
After it said no OS installed, I tried to restore system image from my TWRP backup, and the restore failed and the phone reboot itself at 19% restored. I had to ADB flash the factory system image from google. This brings me back to the original question.
Why was the restore in TWRP failing?
Did you mount system in TWRP before attempting to restore?
Sent from my Nexus 6P using Tapatalk
mistermojorizin said:
After it said no OS installed, I tried to restore system image from my TWRP backup, and the restore failed and the phone reboot itself at 19% restored. I had to ADB flash the factory system image from google. This brings me back to the original question.
Why was the restore in TWRP failing?
Click to expand...
Click to collapse
actually in twrp you could of wiped, then restored boot, system , data and it would of restored everything

TWRP 3.1.1-0 - help me understand what to backup please

Hi,
after few soft-bricks and hours, i was able to transform my stock A2017 B16 to stock A2017U B25 and everything is working.
now the device is B25, android 7.1.1 + TWRP 3.1.1-0 and i want to make full backup as i know the need it if something goes wrong (and it probably will )
in the back up options i see the following:
Boot (64MB)
Recovery (64MB)
System (4740MB)
System Image (6144MB)
Data (excl. storage) (4001MB)
Cach (27MB)
Modem (NON-HLOS) (95MB)
Bluetooth (BTFM) (1MB)
EFS (6MB)
for now, i did backup of all of them but didn't tried to restore because i saw somewhere that i can get you brick .
can you help me understand what to backup for *complete backup* which one i can use in emergency recovery cases?
Boot - This is your bootloader. I usually back this up.
Recovery - This is twrp, you could back it up by itself once, but it isn't necessary.
System - This is your rom and stuff. This is the main thing to backup/restore if you want to keep the current ROM you are on.
System Image - I'm not positive on this, but I think its a full image of the whole system with everything.
Data (excl. storage) (4001MB) - This is all of your personal data, apps settings, call logs, etc.
Cach - no point in backing this up
Modem (NON-HLOS) - I don't back this up either as you can always flash the newest modem files
Bluetooth (BTFM) - bluetooth settings/devices I think, probably don't need to back up.
EFS - Do one backup of this and keep it forever. If you ever wipe or mess the EFS up you are in trouble.
Don't count on all that 100% as I'm not a dev, but I've been doing this for years. Besides the one time backups I mentioned, I routinely just backup the boot, system and data and have never had any problems restoring.
If you are brave and installing a rom that runs on a similar base, sometimes you can backup only the data, and flash the new rom, then restore just the data and have all your settings and apps stuff back.
Hopefully that helps.
Boot, System, Data- just like the person above me.
That's all you really need to do. Sometimes I'll even do things like wipe system only if I'm having problems with the ROM, Gapps, or some random mod, and reinstall the ROM & Gapps to bring it back to a clean slate. Say, if I tried out A.R.I.S.E. sound mod but it was acting goofy and I wanted to make sure I removed all of its remnants.
Recovery is unnecessary I'd think.
EFS - I guess backup once.
Why not backup everything? It doesn't take up much space. System image seems to be the only one I'd leave out. I still back it up anyway.
ThePublisher said:
Boot - This is your bootloader. I usually back this up.
Recovery - This is twrp, you could back it up by itself once, but it isn't necessary.
System - This is your rom and stuff. This is the main thing to backup/restore if you want to keep the current ROM you are on.
System Image - I'm not positive on this, but I think its a full image of the whole system with everything.
Data (excl. storage) (4001MB) - This is all of your personal data, apps settings, call logs, etc.
Cach - no point in backing this up
Modem (NON-HLOS) - I don't back this up either as you can always flash the newest modem files
Bluetooth (BTFM) - bluetooth settings/devices I think, probably don't need to back up.
EFS - Do one backup of this and keep it forever. If you ever wipe or mess the EFS up you are in trouble.
Don't count on all that 100% as I'm not a dev, but I've been doing this for years. Besides the one time backups I mentioned, I routinely just backup the boot, system and data and have never had any problems restoring.
If you are brave and installing a rom that runs on a similar base, sometimes you can backup only the data, and flash the new rom, then restore just the data and have all your settings and apps stuff back.
Hopefully that helps.
Click to expand...
Click to collapse
You're mostly correct except boot, which is the kernel and not the bootloader, and system image is this as mention in an old TWRP changelog:
The Team Win Recovery Project has released version 2.8.7.0 of its custom recovery, known simply as TWRP. This update brings a system read-only option that's intended to help you make a pure backup of your system image that you can later flash to receive over-the-air updates after having rooted or ROMed your device.
Cheers.
@mb0 Basic backup is system data and boot to have a working device, but I'd backup everything at least once just to be on the safe side.
The "backup all" solution sound nice to me??
At least one full backup and i keep it in safe place(es).
Let's try the restore function and hope not to be surprised
Hehe, good luck mate!
I'm back to update...
Full backup (except 'cache') --> reboot to recovery --> normal 'wipe' --> reboot (to make sure that it wiped) --> reboot to recovery --> restore everything (except 'cache') -->reboot --> ITS ALL GOOD :good:

Restoring backup of stock ROM not working well

I take a backup of my stock ROM through TWRP (3.6.2.9) in MI A1. For some reason, I wanted to restore it back, but it's taking too long to boot the phone after the completion of restoring. Even if it boots, then it misbehaves quite often and is not able to use the phone. When I checked the internal storage in the phone, it's saying 0B free although through TWRP recovery it's showing 40GB free from the PC. What's the wrong I'm doing in the process of restoring. I'm restoring all the available partitions such as Boot, System, System Image, Data, EFS, and Android secure. Do I have to leave some of the partitions in restoring process?
I appreciate any kind of help in this regard.
This is a duplicate thread, I request to delete this post.

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