[Sony Xperia X Questions & Answers] Ace2213:
Undetected by PC. Unable to access fastboot, flashtool. "USB devices disabled"

Note 1: I purchased this device second hand in a third world country, so please don't suggest "warranty" or return or service options.

Note 2: Both my computers work perfectly fine with other devices, so please don't waste time asking questions about them. They are fine. My adb configuration is fine. Yes I've tried many, many different cables. This problem is definitely 100% with the phone. The only thing that COULD be computer-side is drivers, but once again, it was connecting normally without any drivers before the "USB devices disabled" warning. I have the latest version of everything with the latest updates. I have followed all the info in all other guides all over the internet.

When I first got this phone, I did what I always do: Enable dev options, enable OEM unlock and ADB debugging. Connected it to PC and was detected normally in My Computer like any other phone. I had no particular Sony drivers installed and no Xperia Companion, only ADB drivers.

I started looking up how to install TWRP, which is the first thing I do on any phone. For some reason, I wasn't able to access fastboot or flashmode on this phone. I tried to access them in adb, but adb wouldn't show the device, even though it appeared in My Computer, had ADB debugging enabled and USB connection type set as MTP File Transfer.

Odd. I installed Xperia Companion, which detected the phone normally, but that didn't make adb work. ̶I̶ ̶t̶r̶i̶e̶d̶ ̶i̶n̶s̶t̶a̶l̶l̶i̶n̶g̶ ̶t̶h̶e̶ ̶o̶f̶f̶i̶c̶i̶a̶l̶ ̶d̶r̶i̶v̶e̶r̶ ̶a̶s̶ ̶s̶u̶g̶g̶e̶s̶t̶e̶d̶ ̶e̶v̶e̶r̶y̶w̶h̶e̶r̶e̶,̶ ̶b̶u̶t̶ ̶f̶o̶r̶ ̶s̶o̶m̶e̶ ̶r̶e̶a̶s̶o̶n̶ ̶W̶i̶n̶d̶o̶w̶s̶ ̶w̶o̶n̶'̶t̶ ̶l̶e̶t̶ ̶m̶e̶ ̶i̶n̶s̶t̶a̶l̶l̶ ̶i̶t̶.̶ ̶I̶n̶ ̶o̶n̶e̶ ̶m̶e̶t̶h̶o̶d̶,̶ ̶i̶t̶ ̶t̶e̶l̶l̶s̶ ̶m̶e̶ ̶t̶h̶a̶t̶ ̶"̶T̶h̶i̶s̶ ̶d̶e̶v̶i̶c̶e̶ ̶i̶s̶ ̶a̶l̶r̶e̶a̶d̶y̶ ̶u̶s̶i̶n̶g̶ ̶t̶h̶e̶ ̶b̶e̶s̶t̶ ̶d̶r̶i̶v̶e̶r̶"̶,̶ ̶a̶n̶d̶ ̶t̶h̶e̶ ̶H̶a̶v̶e̶ ̶D̶i̶s̶k̶ ̶m̶e̶t̶h̶o̶d̶ ̶t̶e̶l̶l̶s̶ ̶m̶e̶ ̶t̶h̶a̶t̶ ̶"̶T̶h̶i̶s̶ ̶d̶r̶i̶v̶e̶r̶ ̶i̶s̶n̶'̶t̶ ̶c̶o̶m̶p̶a̶t̶i̶b̶l̶e̶ ̶w̶i̶t̶h̶ ̶t̶h̶i̶s̶ ̶d̶e̶v̶i̶c̶e̶"̶,̶ ̶a̶n̶d̶ ̶i̶n̶ ̶b̶o̶t̶h̶ ̶c̶a̶s̶e̶s̶ ̶t̶h̶e̶ ̶i̶n̶s̶t̶a̶l̶l̶a̶t̶i̶o̶n̶ ̶f̶a̶i̶l̶s̶.̶

Edit: I successfully installed flashtool drivers as well as the official Sony driver. Still unsuccessful.

I kept reconnecting to different ports and different cables to see if it helps, but I started getting a strange warning on my phone that I've never seen before: "USB devices disabled for using too much power". I ignored it and clicked ok. This showed up twice or 3 times. After that, the phone stopped being detected by My Computer and also Xperia Companion. Windows started warning me upon connecting that "USB Device not recognized".

A̶l̶l̶ ̶o̶f̶ ̶t̶h̶i̶s̶ ̶w̶a̶s̶ ̶y̶e̶s̶t̶e̶r̶d̶a̶y̶.̶ ̶I̶ ̶f̶o̶r̶g̶o̶t̶ ̶a̶b̶o̶u̶t̶ ̶i̶t̶ ̶a̶n̶d̶ ̶k̶e̶p̶t̶ ̶u̶s̶i̶n̶g̶ ̶t̶h̶e̶ ̶p̶h̶o̶n̶e̶ ̶n̶o̶r̶m̶a̶l̶l̶y̶.̶ T̶o̶d̶a̶y̶,̶ ̶I̶ ̶d̶e̶c̶i̶d̶e̶d̶ ̶t̶o̶ ̶t̶r̶y̶ ̶a̶g̶a̶i̶n̶,̶ ̶b̶u̶t̶ ̶e̶v̶e̶r̶y̶t̶h̶i̶n̶g̶ ̶s̶e̶e̶m̶e̶d̶ ̶t̶o̶ ̶b̶e̶ ̶t̶h̶e̶ ̶s̶a̶m̶e̶ ̶s̶t̶i̶l̶l̶.̶ ̶I̶ ̶d̶e̶c̶i̶d̶e̶d̶ ̶t̶o̶ ̶t̶r̶y̶ ̶o̶n̶e̶ ̶m̶e̶t̶h̶o̶d̶ ̶t̶h̶a̶t̶ ̶I̶ ̶t̶h̶o̶u̶g̶h̶t̶ ̶w̶a̶s̶ ̶p̶r̶e̶t̶t̶y̶ ̶s̶t̶u̶p̶i̶d̶ ̶w̶h̶e̶n̶ ̶I̶ ̶f̶i̶r̶s̶t̶ ̶c̶a̶m̶e̶ ̶a̶c̶r̶o̶s̶s̶ ̶i̶t̶,̶ ̶b̶u̶t̶ ̶a̶t̶ ̶t̶h̶i̶s̶ ̶p̶o̶i̶n̶t̶ ̶I̶ ̶w̶a̶s̶ ̶o̶u̶t̶ ̶o̶f̶ ̶o̶p̶t̶i̶o̶n̶s̶ ̶s̶o̶ ̶I̶ ̶f̶i̶g̶u̶r̶e̶d̶ ̶w̶h̶a̶t̶ ̶t̶h̶e̶ ̶h̶e̶c̶k̶.̶ ̶I̶ ̶d̶i̶s̶a̶b̶l̶e̶d̶ ̶A̶D̶B̶ ̶d̶e̶b̶u̶g̶g̶i̶n̶g̶,̶ ̶O̶E̶M̶ ̶u̶n̶l̶o̶c̶k̶ ̶a̶n̶d̶ ̶d̶e̶v̶e̶l̶o̶p̶e̶r̶ ̶o̶p̶t̶i̶o̶n̶s̶.̶ ̶ ̶T̶h̶e̶ ̶p̶h̶o̶n̶e̶ ̶c̶o̶n̶t̶i̶n̶u̶e̶d̶ ̶t̶o̶ ̶b̶e̶ ̶u̶n̶d̶e̶t̶e̶c̶t̶e̶d̶,̶ ̶s̶o̶ ̶I̶ ̶d̶e̶c̶i̶d̶e̶d̶ ̶t̶o̶ ̶r̶e̶s̶t̶a̶r̶t̶ ̶t̶h̶e̶ ̶p̶h̶o̶n̶e̶.̶ ̶I̶t̶ ̶b̶o̶o̶t̶s̶ ̶c̶o̶m̶p̶l̶e̶t̶e̶l̶y̶ ̶a̶n̶d̶ ̶n̶o̶r̶m̶a̶l̶l̶y̶,̶ ̶b̶u̶t̶ ̶u̶p̶o̶n̶ ̶e̶n̶t̶e̶r̶i̶n̶g̶ ̶m̶y̶ ̶p̶i̶n̶ ̶c̶o̶d̶e̶,̶ ̶i̶t̶ ̶c̶r̶a̶s̶h̶e̶s̶ ̶a̶n̶d̶ ̶r̶e̶b̶o̶o̶t̶s̶.̶ ̶T̶h̶e̶ ̶f̶u̶r̶t̶h̶e̶s̶t̶ ̶I̶'̶v̶e̶ ̶b̶e̶e̶n̶ ̶a̶b̶l̶e̶ ̶t̶o̶ ̶g̶e̶t̶ ̶i̶t̶ ̶w̶a̶s̶ ̶t̶o̶ ̶r̶e̶a̶c̶h̶ ̶m̶y̶ ̶h̶o̶m̶e̶ ̶s̶c̶r̶e̶e̶n̶ ̶(̶b̶y̶ ̶d̶i̶s̶a̶b̶l̶i̶n̶g̶ ̶W̶i̶-̶F̶i̶ ̶a̶n̶d̶ ̶m̶o̶b̶i̶l̶e̶ ̶d̶a̶t̶a̶,̶ ̶n̶o̶t̶ ̶s̶u̶r̶e̶ ̶i̶f̶ ̶t̶h̶a̶t̶ ̶m̶a̶d̶e̶ ̶a̶ ̶d̶i̶f̶f̶e̶r̶e̶n̶c̶e̶)̶,̶ ̶b̶u̶t̶ ̶t̶h̶e̶n̶ ̶i̶t̶ ̶c̶r̶a̶s̶h̶e̶s̶ ̶a̶g̶a̶i̶n̶.̶ ̶A̶n̶y̶ ̶a̶t̶t̶e̶m̶p̶t̶ ̶t̶o̶ ̶a̶c̶c̶e̶s̶s̶ ̶S̶e̶t̶t̶i̶n̶g̶s̶ ̶i̶n̶s̶t̶a̶n̶t̶l̶y̶ ̶m̶a̶k̶e̶s̶ ̶i̶t̶ ̶c̶r̶a̶s̶h̶,̶ ̶a̶l̶t̶h̶o̶u̶g̶h̶ ̶a̶c̶c̶e̶s̶s̶i̶n̶g̶ ̶s̶p̶e̶c̶i̶f̶i̶c̶ ̶s̶e̶t̶t̶i̶n̶g̶s̶ ̶m̶e̶n̶u̶s̶ ̶t̶h̶r̶o̶u̶g̶h̶ ̶Q̶S̶ ̶(̶l̶i̶k̶e̶ ̶m̶o̶b̶i̶l̶e̶ ̶d̶a̶t̶a̶)̶ ̶o̶p̶e̶n̶ ̶f̶i̶n̶e̶,̶ ̶b̶u̶t̶ ̶i̶t̶ ̶s̶t̶i̶l̶l̶ ̶c̶r̶a̶s̶h̶e̶s̶ ̶a̶f̶t̶e̶r̶ ̶a̶ ̶c̶o̶u̶p̶l̶e̶ ̶o̶f̶ ̶s̶e̶c̶o̶n̶d̶s̶.̶

Edit: Reboot has been fixed with a factory reset via Support > System > Factory reset during the short uptime of the device before it reboots.

This phone is 100% stock, Oreo, latest updates. Zero root exploit attempts have been made. I activated Substratum's Andromeda via PC but Substratum still told me that it didn't work, so I stopped trying. I also side-loaded some APKs (all trusted, none of which on the system partition), but that's about it.

I've also tried connecting it to my laptop with no difference. The exact same behavior, so it's clearly the phone itself.

Clearly, the key to all of this is finding a way to access fastboot and flashmode, but for the life of me I can't get either to work. I follow the instructions and get a red LED that gets stronger if I keep holding down the VOLdwn button and the Sony splash screen followed by the charging animation. VOLup never does anything, it boots normally, unless the power button is also pressed which makes it vibrate 3 times, apparently signaling that the device was powered off.

Also, figuring out why the charging port ("USB Devices") seems to have been disabled (as per the warning message) and how to re-enable it. From what I've read, this typically happens when moisture is detected in the charging port and is done to protect the phone from over-voltage. However I have not used this phone anywhere near water since I've gotten it. And it was initially being detected normally.

I saw some great guides made by [MENTION=8052364]FoxTheLegend[/MENTION] and [MENTION=5613633]YasuHamed[/MENTION] for this phone and I was hoping they'd be able to lend their experience to help me figure this out. I've never been completely locked out of a device like this in a way that I was completely unable to solve, and I've dealt with Samsung devices with FRP and the 7 day thing.