• Introducing XDA Computing: Discussion zones for Hardware, Software, and more!    Check it out!

Samsung Galaxy S7 Boot loop

Search This thread

xAxB

Member
Mar 9, 2017
45
9
Well, this is rather vexing.

I've been hard at work trying to backup / transfer data from my extremely old Samsung Galaxy S5 that seems to be coming to the end of it's useful lifespan. The S7 was next, but aside from running out of internal storage, I thought I still had time on that one (I wasn't experiencing a lot of slowdown or any crashes).

I went out for a couple hours (taking my newer phone), and when I came back, I saw my S7 on the insert the pin code screen. When I put the correct pin code in, the "unlocked padlock" stays on the screen for ages, before the phone restarts and I am shown the pin screen again (if I insert the wrong pin, it says so, so I am sure that I am not inserting the wrong pin).

So for the first time in my life, I am dealing with a spontaneous boot loop. This device has never been rooted, had a custom recovery installed or even the bootloader unlocked (it's the Exynos version, so presumably it would have been possible, but I decided that I wanted *one* unrooted device just in case, and given Knox, I decided that this was the device that will remain unmodded).

Anyway, that's for the story, but the question is, is there anything that I can try before the nuclear option (factory reset etc.).

Fortunately most of the photos are on the MicroSD. There are perhaps two or three apps that I would have liked to backup (they did not have a convenient built-in backup system) but I am just wondering if there is anything I might be able to do at this point? For instance, would wiping the cache be an option? Or is there anything I might be able to do with adb?

(Note: The device is running on Android 7)

Thanks.
 

blackhawk

Senior Member
Jun 23, 2020
7,214
2,734
Don't set security passwords for device access as you are the one most likely to be locked out.
If the boot loop wasn't caused by a hardware failure it's likely a app you loaded. Launchers and power management apps are prime candidates. Leave at least a couple gb of headroom on internal storage.

A factory reset is the easiest solution. Be careful what you load next time... take out the trash.
Use the SD card as a data drive, all critical data and everything you need for a reload goes here. No apps. Only apps, and the temporary download folder go on the internal memory.

The DCIM folder can be set to the SD card as well, but there can only be one DCIM folder and don't change its name. If a second backup folder is used on the SD card instead do not name it DCIM.

ApkExport can be used to make installable copies of apps for transfering them and added the data drive as well, no Playstore needed.
Do not use Kies or SmartSwitch when going between different type devices or OS versions. It can cause issues.
Cut/paste critical data, verify the data is readable and all there. Don't trust Kies or SmartSwitch with critical data.
Never clone data drives.
Never encrypt data drives.

Regularly redundantly backup the SD card data drive to at least 2 hdds that are physically and electronically isolated from each other and the PC.
 

xAxB

Member
Mar 9, 2017
45
9
Thanks for the reply.

1. No app was recently installed (past couple of weeks)
2. Hardware failure? Maybe, but it is rather out of the blue. Phone has not displayed any unusual behaviour, it hasn't been taken out of the house for a week or so (it is really in the process of getting retired). And I would like to ascertain it.
3. I am aware I can just nuke the whole thing with a factory reset, but before taking that easy option and effectively lose some data I'd like to retrieve if possible, I would like to other options.

And rather than tips on what I should've done or can do next time (much of which I am already doing), I am looking for advice on anything I might be able to try -before- nuking the whole thing.

For instance, could the log-files (there are quite a few of them) provide hint in what went wrong? Any option of re-installing the OS without wiping the data partition? Since I am on a fairly old version of Android I may also have the option of doing a minor update. That kind of things. I am thinking that there might also be the possibility that the system files somehow got corrupted and perhaps a re-install or system update might be worth trying.

I am basically looking for options that will not, for the time being erase the data partition. If it comes down to it in the end, then fine, but that is the last option not the first.
 
  • Like
Reactions: blackhawk

blackhawk

Senior Member
Jun 23, 2020
7,214
2,734
It sounds like it got spontaneously corrupted. Perhaps a flash memory cell failure. If so it may or may not be "self healing" with a factory reset or a reflash.

If you have ADB access you may be able to fix it.
Otherwise your options are limited to what's on the boot menu.
Try doing a hard reboot (simulates pulling battery).
If you try booting it a bunch of times it may go into go safe mode. I've seen that behavior in Android 9.
That's extent of my skills, sorry.

The reason why I posted how to prevent data lose is because sometimes that's all you can do.
Internal memory data I consider expendable, the SD card data... potentially expendable.
 

Top Liked Posts

  • There are no posts matching your filters.
  • 1
    Thanks for the reply.

    1. No app was recently installed (past couple of weeks)
    2. Hardware failure? Maybe, but it is rather out of the blue. Phone has not displayed any unusual behaviour, it hasn't been taken out of the house for a week or so (it is really in the process of getting retired). And I would like to ascertain it.
    3. I am aware I can just nuke the whole thing with a factory reset, but before taking that easy option and effectively lose some data I'd like to retrieve if possible, I would like to other options.

    And rather than tips on what I should've done or can do next time (much of which I am already doing), I am looking for advice on anything I might be able to try -before- nuking the whole thing.

    For instance, could the log-files (there are quite a few of them) provide hint in what went wrong? Any option of re-installing the OS without wiping the data partition? Since I am on a fairly old version of Android I may also have the option of doing a minor update. That kind of things. I am thinking that there might also be the possibility that the system files somehow got corrupted and perhaps a re-install or system update might be worth trying.

    I am basically looking for options that will not, for the time being erase the data partition. If it comes down to it in the end, then fine, but that is the last option not the first.