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.
Samsung Galaxy SM-J700F
Security Patch Level - 2016-07-01
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!