Hey everyone. I know this thread is like super dead but instead of making a new one I will just post what I found here.
After a lot of searching, I found this thread here that we are on and that lead me back to this being either a motherboard issue or an issue with a 3rd party flex cable. I REALLY didn’t want it to be a motherboard issue on top of the fact that I was very careful in handling the motherboard as I know breaking it would lose all data and require FaceID replacement as well. So I held out hope.
After reading about another similar issue I read a post that gave me the idea to check crash logs or system logs to see what might be causing the crash. Sys Logs were a bust as they only showed active processes, so I moved on to crash logs/dumps which apple so graciously provides us with under Settings -> Privacy -> Analytics & Improvements -> Analytics Data.
Now that I was there I only had a few minutes before the phone would restart so I had to act fast but there were so many different dump types that I had no idea what the names meant. Some were app specific referencing the AMC Theaters app while others were Aggregates from the day prior. I was able to see that there were a lot more dumps from one specific type, and that was called Panic-Full. This got even more interesting when I looked at the most recent timestamped file under the many many panic-full files that were dated and timed the EXACT MINUTE the phone turned off and subsequently turned on.
After a few quick google searches, I found this Apple support thread from Oct 2019 with one particular post that was pretty recent (Jan 2020) from a user by the name of HydraKiller and it went like this
Jan 7, 2020 9:49 PM in response to mosa144
Related to the charging flex cable port, Solved this simply using an original salvaged charging flex cable, 100% fixed. Some aftermarket charging flex cable aren’t working on iOS 13.x, They’re messing with something related to the thermal system, and forcing a kernel panic. (PS=The phone will keep restarting without any charging port,too).
to which the OP responded
Jan 15, 2020 12:23 AM in response to HydraKiller
Your reply saved my phone!
Hope my experience + your solution can help others...
Had some water spill onto the phone while charging which was discovered too late. Phone would no longer turn on, and the USB port looked damaged. Removed the screen and discovered that water traveled into the bottom of the phone so I removed major components from the bottom up until I could be sure all was dry and then let sit 48 hrs to be sure.
Phone finally powered back on, but went to recovery mode and requested I plug into itunes. itunes could not resinstall iOS and kept giving me 4013 error.
At the store, Apple said my phone was gone and to buy a new one - "nothing they could so." A local repair shop said $150, and they could replace the motherboard, but couldn't guarantee anything. FYI, replacing just the motherboard also means FaceID stops working as the camera and board are tied together.
However, since the source of the initial issues was the charging port, I bought a new USB flex and lo and behold, Itunes was able to reinstall the iOS! After patting myself on the back for the $8 repair, I reassembled the phone but discovered it powering off every 3 minutes to the dot. Spent hours trying to diagnose, and ran into many posts about the 3 minute restatrt, but no solutions. Much was attributed to a bad motherboard. Finally stumbled upon this lone reply which suggested my "new" USB flex was actually bad, which was further supported by iOS diagnostics error log showing me that every 180 seconds it was shutting down because it was getting a thermalmonitor error.
Long story short, another new $12 USB flex later from Amazon, and my iphone X is now completely operational.
Basically all this is saying is that sometime after IOS 13 got released, something in that update caused the phone not to recognize one or more of the thermal sensors that are part of the flex cable connected to the charging port. From what I can read by the OPs final post he did not end up getting a refurbished/salvage flex but he was able to opt for not the bottom of the barrel when it came to replacement parts and got out just fine. On top of that if you do not have a known good OEM charge cable even leaving the cable unplugged causes this kernel panic.
I am still looking to see what cables are readily available for purchase and I will get back to you with a link.
Here also is a link to the original apple thread.