[Sprint Samsung Galaxy S III] VasVadum:
Ok, first off I chose Sprint because I believe that Boost Mobile is on the sprint network, but my phone doesn't specifically say sprint on it or anything, so I had no clue which of these device boards to post into. This is the exact page I got it on, if that helps. [link deleted - paranoid forum rules] - I will post specs of the device in a minute.

Alright, the issue with my phone, is that after I used a car charger 2 months after I got my phone, it suddenly stopped being able to connect to ANY computer ever again. I suspected it was PDA net at first cause that was the newest change I had done to my phone. So, a few days later, I could find now way whatsoever to fix it, and had to factory reset. This fixed my phone just fine.

Two months later, I was fed up with having battery issues all the time, this phone drains battery faster than my laptop, and its battery is 3.8 years old! I got an external battery that holds 20,000 mAh/74 Wh (Practically the same as my laptop battery too. :P) that is from the LimeFuel company. I know that before I used it, my phone worked with my laptop just fine. I don't plug my phone in to my laptop all that often, especially now that I have a battery to use with it. However, I download large files on my phone with 4G to put onto my laptop because my home net is crappy, so a week after, I noticed that my phone lost the ability to communicate with computers, again. I then realized, it had to be the connections. The first time it happened was when I used a car charger, the second time, an external battery. Each time, my phone suddenly inexplicably lost the ability to communicate with a computer ever again. It can only see devices as a power source, nothing more. There's no missing software or drivers, it just doesn't register as anything to my computer. Like a power toggle so it can't tell the computer "Hey, I'm a device that you can transfer data with".

One more note; The first time this happened, I had activated developer options but had them turned off. I mean that I used USB Debugging mode once and turned all of that off. The second time, I hadn't even unhid the option yet, unhid after my phone broke again to try and fix but nope.

I did research on trying to fix it, without factory reset because a factory reset is USELESS, if it's going to happen every single time I use anything but the wall to charge it, right?

There was a topic online claiming that there is a menu under "Storage" in the settings. There isn't. It was a big fat lie. Or Android devs deleted it.

There was another topic, claiming that USB settings would be under some wireless and networks area. Nope.

Now, I remember that when my device would connect to the computer, it would let me change it from MTP to PTP, but after this happened, nothing. It doesn't even pop up anymore, nor does it ask. There is no where in the phone that these options even exist at all. It's like Android devs deleted access to these options for no reason whatsoever.

Another bit in that topic mentioned ‘USB Mass Storage’, which also doesn't exist. Here's the topic with everything I tried, if I'm allowed to give links at all. If not, well not my fault. Topics used to try and diagnose and fix issues, but failed;

[link deleted - paranoid forum rules]

[link deleted - paranoid forum rules]

(There were more but I can't remember them all, it's more or less the same as the two above)

"To prevent spam on the XDA forums, ALL new users prevented from posting outside links in their messages. After approximately 10 posts, you will be able to post outside links. Thank you for understanding!"

Translation: "To prevent spam, we want to hinder only legitimate users by making them post 10 units of spam first before they can get help with their issues by showing exact information and screenshots of their issues or steps taken given by other websites."

So. How do I get my phone to connect to computers again?

Why does it stop accepting data from computers after I use a car charger or an external battery pack?

Why would Google/Android devs choose to intentionally break your phone like this?

Hardware: L710T.03
Software: L710TVPU0AOA3
Model: SPH-LT10T
Android 4.4.2
Kernal: 3.4.0-1683363 (Ask if need more)
Build: KOT49H.L710TVPU0AOA3
Ask of need more.