This the best note app ever, from old good Sony soft department days when they tried to innovate and develop their own Xperia unique apps instead of today's going the easy way and preloading Google ones:
Found a petition - not sure if that helps, but it worked in M2's case, so probably worth a try:
(if I'm breaking any rules, feel free to remove problematic content)
if I can't install twrp without a custom rom then how do I install a custom ROM without a custom recovery?
Custom ROMs usually comes with recovery packed in boot.img. If not, try flashing TWRP as boot.
Problem is that I didn't receive an update notification, and the tool on Windows (i think it was called pc companion or something like that) didn't find updates.
Is there maybe anywhere a 4.3 backup done in cwm? Then I could flash it using cwm as...
1. You should upgrade to 4.3 (I think latest is 15.4.A.1.9) before flashing anything
2. Yes, flashing any ROM will replace your /boot.
3. Flash TWRP into FOTA kernel.