Found the bug in Geany editor with underscores - they were invisible. Default font is Monospace.
Here is a solution how to fix it.
Chinese tablets it's not only the cheap price, but in uther cases it's not funny surprises. It was the first time I've met the problem, when the stock firmware has a virus/malware. Couple of them.
MediaTek MT8392 processor, it's the twin of МТ6582. First is used in tablets, second in phones. I want Cyanogen to run on this device, but didn't found one. I thought that it would be great to repack cyanogen mode myself. Sources are available across the net. But I keep calm, sit down and start to struggle with virus.
Common user most of time doesn't care about RAM of his android device, about processes that running on background etc.
User who know what is RAM install apps to clear it. But we are not common users and wont install apps to kill. We gonna kill them ourselves.
You must be root, have busybox and terminal emu installed.
You can use am force-stop <package name>.
or am kill <package name>.
am kill only kills "processes that are safe to kill": i.e. a process with no running services or activities.
One day my phone got veeeeeery slow. Killing apps in Settings — Application is not the real way for me and I started to Terminal. Of course, my device rooted. So, all command done in SU mode.
I saw a weird (lol) proc called system_server. So I decided to kill it. He he. Device did soft reboot and display rectangle with text «Safe mode» in left bottom corner.
$ ps -m 10 -s vss
Weird, I think) I actualy did nothin. Netwrok was working, so I open browser to search the answer.