reboot problem summary
I think there is new bug on TWRP.
--- I'm on Xperia C6603 , LOCKED bootloader, ROOTED, NOT install any bootloader, no reboot problem at all. Uninstalled widget/wallpaper using Titanium backup , deleted, modified file on /system with root explorer, all good. No reboot problem at all.
--- Installed TWRP recovery, right after it done and phone on recovery, choose reboot right away. I AM NOT HAVING REBOOT problem right now!! (WHAT??) , tested by titanium uninstalling a couple things (mostly widget / wallpaper). <~~~~~~~~ Actually I uninstalled about 4 wallpapers, 2 widgets, 2 apps, and it DID NOT REBOOT at all. I think I should back to stock rom, with TWRP and test more on this.
-- Now reboot to TWRP recovery, Sony logo, green LEDt, press VOL UP couple times, it goes to recovery, but FREEZE. Touch screen not working, power button not working. LED stay at purple. <~~~~~~~~ NEW BUG??
Install TWRP again using package run on Windows, still freeze.
-- Now use flashtool to reflash stock rom (clean data/cache as well). Root, install TWRP recovery, install RomAur 1.3.2, flash the TWRP recovery zip file. Reboot (it asked to fix root permission, I choosed "NO"). Using titanium backup to remove wallpaper (name: black hole). PHONE REBOOT!!!! <~~~~~~~~ reboot bug that everyone talking about.
-- Go into recovery with VOL UP on green LED. Success. Touch screen working. Try fix permission (TWRP-> Advance -> Fix permission), reboot system. Sony logo showed, xperia logo showed, startup loaded, PHONE REBOOTED. Now use titanium backup to uninstall wallpaper (Bubbles 1.0), uninstall app (wise pilot), phone REBOOT after a while
-- Turn phone off, go to TWRP, click something to make sure it works. IT WORKS. Now reboot system, Sony logo showed, xperia logo showed, startup loaded, PHONE REBOOTED. After 6 times boot loop, it goes to lock screen finally. Titanium backup to uninstall apps, still reboot.
After 1 hour of messing around, I realised the difficult thing to test this bugs is it DOES NOT REBOOT right after unstinall 1 apps. It happen randomly!!! So I decided to back to stock rom +TWRP and test more.