Hey bro,
I have the same problem with repeated reboots,
I'm on slim XXUCNJ1 version,
the phone overheated very bad, at one point I was even scared.
It was very hard to make it stop, take about 5 seconds after starting and restarting, in those 5 seconds I struggled to open SetCPU and set it something around 1000.
That was stable and restart in 15 seconds, during which I was able to copy the kernel nonOC so I can install it with TWRP.
It was like old times, in a in a thrilling computer game...
Unfortunately when I installed the kernel does not know about soc_pvs file and not looked after number.
I looked now, after I installed kernel nonOC and the number is 2.
I encountered another problem and do not know how to interpret,
since I installed SetCPU, in all 3 kernels, 1 nonOC and 2 OC,
I found that the UI go heavy, clinging like,
I thought it was from an application that cup storage too much or something like that.
Now, after I returned to nonOC, I wiped data and cache op SetCPU and I did't
open it, so no set, and now UI go smooth... hmm?!
(After each new kernel, I wipe cache and dalvik cache.)