Legit Adroid download or hack attack?

Looks like you've been had by a virus. Never download from an unknown source, no matter how good they seem. You can always do a spam/scam check on any download. https://search.yahoo.com/yhs/search;_ylt=AwrWmn197htdNH4AiQIPxQt.;_ylu=X3oDMTEwbHI2ZzczBGNvbG8DZ3ExBHBvcwMxBHZ0aWQDBHNlYwNyZWwtYm90?p=how+to+check+on+spam%2Fscam+downloads+folder+on+mac&type=1744376776&hspart=pty&hsimp=yhs-pty_converter&param1=20190529&param2=59b60d0b-7323-44a1-abc2-1f111a0429b0&param3=converter_%7EUS%7Eappfocus1&param4=g-ccc3-lp0-cp_1744376776-bb8-sfnt%7ESafari%7Ehow+to+check+on+spam%2Fscam+downloads+folder%7ED41D8CD98F00B204E9800998ECF8427E&ei=UTF-8&fr2=rs-bottom%2Cp%3As%2Cv%3Aw%2Cm%3Aat-s&fr=yhs-pty-pty_converter

That's a legitimate screen, called Odin mode, something unique to Samsung devices. What's your model of Samsung? Do you know the Android version on it? And did anything happen before that like trying to update?

Thank you very much for replying. My phone started to act up, e.g. freezing, rebooting by itself. I even did a factory data reset of the phone. The problems continued after the reset. My phone's a Samsung Note 4, Android version 6.0.1. I had never seen that screen before in other Android updates.

Happy to help, if I can. Samsung is a bugger to work with and I'm not too familiar, but I've messed around quite a bit with rooting (and occasionally screwing up and then fixing) several devices over the years.

You said you performed a factory reset. What steps were taken to do that?

To do a factory reset there's a button in Settings for that.

The phone seems to have improved. It's not freezing or rebooting anymore, but there's a faded icon in the upper left corner.

Okay good. I thought the phone was stuck on the Odin download screen. You can also factory reset the device, as well as wipe the cache partition, from recovery mode.

The white spot on the screen is an oddity. It doesn't look like an icon to me, given it's positioning half in and half out of the status bar. Assuming it's not an icon that can be tapped, I'd table this one for the time being.

Since the device is up and running, the first thing I'd do is make sure everything's backed up, if you haven't done so already. Also try to think if there are any apps you've installed recently. Maybe there's something new that isn't playing nice.

If the phone is acting buggy, try running it in safe mode for a day or two and see how it does. In safe mode, only system apps are available – all third party apps are disabled. So essentially, only apps that the phone came with will work. Bonus: you'll likely notice it has a bit more zip to it, since none of the processes and services of third party apps will be running. How to access safe mode

If it seems to do better in safe mode, consider deleting any apps and files that you don't use anymore. Actually, consider doing this regardless. If you're near your storage capacity, this can supposedly cause performance problems. Note that system apps can't be deleted, but some may be carrier (Verizon, at&t...) and manufacturer junk – often referred to as "bloat", that can be disabled. You can also delete the storage of those apps.

That's probably enough for now. Hopefully you get on alright with it!

How do feel about this?