Does Downgrading from Android Marshmallow to Lollipop wipe data?

[AC Question]

After an OTA upgrade to Marshmallow, Android Locksceen is no longer accepting my 4 digit PIN, I have been using this PIN for the past 7 months without any problems. So, I know for sure that I haven't forgotten the PIN. Nobody else has accessed my device & changed the pin.

I had 2 other backups of my Data, one on a SD Card in my Canon EEOS 700D DSLR(I am a Professional Photographer) & second one on My Laptop, both of them were stolen from the hotel I was staying at. My phones Internal Storage is now the only other place that has my work. I don't care about recovering music, videos, contacts, messages. I am only interested in recovering my clients pictures (Wedding Photographs). I just can't afford to lose this, please do not suggest Factory Reset. If it wasn't that important to me, I would have done Factory Reset.

Device Information

Samsung Galaxy SM-J700F

Android 6.0.1/MMB29K/J700FXXU2BPG3

Security Patch Level - 2016-07-01

No Root

No USB Debugging

No Custom Recovery

Boot Loader Locked

No Full Disk Encryption, Only Lockscreen

Samsung Find My Mobile Not Registered (Even if it was, it wouldn't work without WiFi or Mobile Data turned on)

Can't turn on WiFi or Mobile Data from Lock Screen, so Google Android Device Manager also not working.

Can only access Emergancy Dialer & Camera from Lockscreen

Since the problem appeared right after the OTA upgrade to Marshmallow, would downgrading back to the previous version using ODIN Flash Tool fix the problem? Now, with a locked bootloader, you can't flash anything other than official Firmware signed by Samsung, so, if I download Official Samsung ROM Android 5.1.1 Version from www.sammobile.com , and flashed it using Samsung ODIN Flash tool, would it wipe all the data in internal storage? or would it stay intact? Help Please!

 

[Tim1954]

I posted this on the mods site, hopefully some clever person will be able to assist you...

 

[hallux]

To revert to an older OS I believe it WILL wipe all your data. If you're going to end up with that result, why not just do a factory reset and start over with the new OS instead?

 

[Ry]

To revert to an older OS I believe it WILL wipe all your data. If you're going to end up with that result, why not just do a factory reset and start over with the new OS instead?

The OP can't afford to lose the data.

 

[Aquila]

Do you know the backup password if your pin were to become locked out?

 

[Rukbat]

There's no such thing as 'downgrading' an OS version, unfortunately - the old code just isn't there any more. Your only hope is that the update didn't install fully, and your carrier can reinstall the update (the update only, not the OS or 'the ROM'), and get your lock working with your old PIN again.

Otherwise start keeping a list of the last PIN you tried - it's going to be a long process of trying a pin, shutting down, starting, trying the next PIN, etc., and there are 10,000 possible PINs (0000 is a number) - start with 0000 and work your way, 1 by 1, to 9999. And that's assuming that it's not the unlock code (computer code, not the PIN) that's the problem - if it is, the phone won't unlock, period. That would mean that, short of a JTAG (and that's a possibility, not a guarantee), your data is gone.

JTAGing the phone might be enough to get the data back, but you'd have to look on eBay for someone who JTAGs the J7F (in India or Thailand, I'm guessing - that's where the phone is made for). And, as I said, possible but no guarantee. They have to be able to get at least to the Linux level, and you have to hope that the pictures aren't in a place only accessible to some app. (Standard Linux file access policies on an Android phone - owner, group and everyone.) Or run Android with the JTAG and copy the files to the SD card.

(JTAG = Joint Test Action Group. It's the common name for what was later standardized as the IEEE 1149.1 Standard Test Access Port and Boundary-Scan Architecture. It's basically a box that connects to the microcontroller, allowing the user [the guy you're paying to do this] manually "be" the processor and run commands even though Android may be running and blocking your access. He can kill Android, then copy files, or run Android again [the Dalvik machine, actually].)

(Going through all of this, when updates are sometimes forced into the phone [you can say Later only a few times before the update goes without asking you] is why, when shooting a lot of pics, I either just save to the SD card [some camera apps allow changing, and on a rooted phone anything can be given full permissions to the SD card - mine gives everyone permission, so any app can write to it] or the app saves to internal storage and I copy to the SD card every few shots. So if the phone gets locked [or even unfixable permanently], I have everything on the SD card. Which then gets backed up to my desktop and 2 cloud accounts. I've been in this game too long for that animal to bite me again. [Yes, backups do rarely, but they do, sometimes just disappear, even from a site like Drive or Dropbox.])

 

[itguyjax8430]

Have you tried using the Android Device Manager site to reset the pin code?

 

[pkcable]

We brought in a LOT of help here, please join the site so you can reply in this thread and let us know how you made out. See this link for instructions on how to join Android Central.

Wishing you the best of luck getting your pictures back! Are you certain you were not using google photos to back up your photos? Please check at http://photos.google.com

 

[Ry]

...all that said, I've never seen an OS update change a PIN or password/passcode.

 

[Ry]

Have you tried using the Android Device Manager site to reset the pin code?

The phone can't get into a state where it would connect to a network because the PIN/password is unknown.

 

[pkcable]

The phone can't get into a state where it would connect to a network because the PIN/password is unknown.

I think he means the ADM website.....

https://www.google.com/android/devicemanager?u=0


Although I'm NOT sure you can reset the PIN or password from that site.

 

[Ry]

I think he means the ADM website.....

https://www.google.com/android/devicemanager?u=0


Although I'm NOT sure you can reset the PIN or password from that site.

But changing the PIN or password from ADM wouldn't matter since the phone itself cannot connect to a network. If I'm reading the original question correctly (also notice, the user hasn't returned or signed up to continue this conversation), the phone boots to the startup PIN/password screen. Android has not started. At this point, having a working SIM or access to a known WiFi access point is irrelevant.