Thanks, but if there's a solution without having to reinstall the rom: I'd very much prefer that.
It's ridiculous to do so, takes me hours to first backup all stuff, then reinstall and then restore all backup data.
I was hesitant to, but considering I've been dirty flashing even the migration/partition/merge I figured I should. It took me minutes being occupied with the phone, and the phone itself was working for an hour or so, including the "down" time for ten minutes. My phone has been speed up very much!
I will write a quick guide.
But first coffee.
Get ready, and install/buy titanium pro, if you don't have it yet.
Okay:
0) skippable step : I personally remove huge apps that don't need backups ( because they are web based/redownloadable/don't have specific user data) like Facebook, Messenger, Waze, Maps etc. Saves me backup time/space and these apps I will not forget tov reinstall as they are essential.
1a) backup every app. I use Titanium Backup Pro. So I select backup all user apps and data. (Menu > batch actions > backup all user apps.)
1b) also make a backup of a system (red colored) app called System Launcher.
Or combining 1a and 1b in one step: choose " backup all user apps and system data ".
Meanwhile you could do a complete backup of you 'SD card' / storage to your computer. Advisable, just in case, but I didn't bother.
2) scary part: Factory reset, but leave the storage intact! This took quite some time, and I thought uhoh. Just let it run. Your phone will greet you with a start-up screen. You will have to add your credentials manually. So Google settings and Wi-Fi. Should not be that hard.
(And if you check file explorer, don't freak out like I did. It seemed my phone was emptied of my pictures and all, but apparently it need time to rebuild/reindex the phone. )
3) reinstall Titaniumb Bankup again from the market.
4) open TB, and restore all user apps. ( not system Let it run. This takes some time as well. Do not start cleaning your screens / layout yet. I have a nifty trick for that!!
5) remember step 1b) ?
Restore the System Launcher. Data only. And see...
You're done. Except widgets
all your screens / layout are restored. This always took so much time, I hated it. I wish someone told me. So there. ^^
This nifty trick is the best of this entire post.
Obviously you'll be missing system settings, but I found that other than reviewing some permissions, background image, greenify it is very little that I actually missed. And this way I don't migrate faulty system settings.