Locked out of phone and then it tries installing a custom OS

[AC Question]

Some background....

I have a Samsung Note 5.

I was traveling abroad and suddenly started getting web address intercepts with my new temp data card. Last night my screen was taken over by a notice that I had a virus and needed to download 360 Security to fix it. I terminated the app that did that and got out.

I then downloaded several major antivirus apps. None of them could find any viruses or malware. Finally I downloaded 360 Security direct from the Play Store and it couldn't find anything.

Phone ran out of power and when I charged and rebooted it, suddenly it tells me my fingerprint does not match. I never used my fingerprint to try to open it. It also won't accept my backup password or any of my Google account passwords. (I've since changed those)

So I go to factory reset my phone. Instead of the boot screen giving me the option to factory reset, it shows me a warning saying "Installing a Custom OS is dangerous". I power back off, swap out my international card for my Verizon card. Reboot to that "Custom OS" warning, hit the home key to give it the go ahead to start downloading then I interrupt the download so I can get to the correct screen and (with much angst) factory reset. :'(

Upon booting after the factory reset, I'm told the Computrace agent has stopped, which I've heard can get hijacked.

My Question: What the hell happened here? Is my BIOS infected with a virus? How did a custom OS even get on my phone?? I NEVER download anything other than super high user mainstream apps.

 

[chanchan05]

Has anyone had access to your phone? Or have you gotten to a site that asks you to install something?

 

[ShrewdSimian]

No one has had access to my phone other than the guy at the kiosk that installed my SIM card and I watched him every step of the way.

I've gotten redirected to sites numerous times past few days suggesting I install something. At first I ignored it as just spammy sites, then yesterday I realized something was really amiss because it happened with every site. I never installed anything from any site though.

 

[chanchan05]

I'd be wondering why you needed a guy to install the sim card. Anyway, have you tried booting to safe mode? In general for Samsung, you turn off the phone, then you press on the power button and volume down at the same time on turning it on. Once the Samsung logo appears, let go of power button but keep pressing the volume down until you see the home/lockscreen. There would be a small text saying safe mode, usually on the lower left. If you can get it that way, you'll be able to retrieve your data before factory reset.

 

[AlphaTango414]

The "custom rom" warning is a Samsung thing and normal when you first boot into download mode. If you were trying for recovery then use Vol up and not down. .

Now, for the password issue, see Forgotten Password thread.

Virus you say? Check the Malware / Adware Removal thread.

 

[ShrewdSimian]

Tried booting into safe mode. Still couldn't get past the password lockout which was affecting every account and my backup password.

 

[Desiree Hooyman]

It won't let select factory reset, or any of them on that list. @chanchan05

 

[Jake098]

How do i unroot my samsung tab gt p1000