How to resolve a mount problem at system level? (rooted)

[xarx00]

I have a rooted LG G2 mini with Android KitKat 4.4.2.

I installed an application that moves app files from the phone to the SD card. During a moving operation the application crashed. Since then, my phone was freezing after a minute or two after reboot, with the phone rapidly slowing down and finally with the screen turning black. The same behaviour as if the system memory run out, I guess.

I uninstalled the application, and succeeded in finding out that if I rename the ("obb" and "data") folders created by the application on the SD card, the phone stops freezing and works again. The problem is that when I rename the folders back, the phone starts freezing again, even when the problematic application is already uninstalled. The application evidently corrupted some configuration files in the system. As the author of the application is not responsive, I need to find out myself what files were corrupted and fix that manually. Can you advice me where to look at?

Details:

• The problematic application was the "GL to SD" app on the GooglePlay market. It probably does it's work by mounting the moved app content from the SD card to the original location.
• I'm not an Android system hacker, I just know some basics. However, I already found some logs and config files, but I found nothing suspicious in them. Another problem is that some logs seem to get cleared on reboot, so I don't know how to get the logs I need. (As the only thing I can do after the phone freezes is to reboot it.)

 

[Golfdriver97]

The only thing i can think of to fix it is to flash either the stock ROM or a rooted custom ROM onto your phone. Do you have a custom recovery, like TWRP or CWM?

 

[xarx00]

I hope I can flash the ROM, there are stock ROMs on the internet with instructions. For LG G2 Mini, there are snags however, it's not straightforward. And I never did that. I'd prefer to avoid this anyway, because I've invested a lot of work to adjust the phone to my needs.

There should not be too many places where the things could be broken considering my problem description, if Android is not more complicated than say Linux, should they? And if we don't consider the application a malware by purpose. I'm able to provide even more details. Moreover, I have one other such phone, untouched, not rooted. I could compare some particular files on both phones, though I'm afraid that until rooted, the key files won't be readable. But I don't know which files to compare.

• Where can I find the log that contains the system freeze problem report? If there's none, how can I turn its generation on? As I already mentioned, the key logs seem to get cleared on reboot.
• Renaming the moved directories on the SD card resolved the freeze after reboot, so there probably was a boot-time mounting operation that fails now because it cannot mount the directories. And there should be a log about it. Where to look for it? I already tried to look for the log in some mounting-related logs, but found nothing.
• It's hard to search for anything on Android if even such basic posix commands like "find" are missing there. Any suggestion?
• What else could I do?