Okay I've currently got a problem with my phone.

The short version: It's a Galaxy S4 (I9505) with 4.2 JB. After upgrading to KitKat and sideloading a mod, the phone is acting dodgy. It reverted back to 4.2, takes a while to start up now and the Wi-Fi doesn't work. Also ODIN won't let me replace the ROM (though I can still root and install recoveries)



The detailed version: I've been running a rooted I9505 Galaxy S4 (o2 UK stock ROM). Aside from the root and uninstalling some bloatware I made no real modifications.

Because I'd uninstalled apps with Titanium Backup instead of freezing them it made doing the standard firmware upgrade tricky so I did a factory reset (after backing up my settings). Currently it's on stock 4.2.

I upgraded to the official 4.4 firmware and some issues came up. the Wi-fi didn't work and I was getting security issues regarding user privilege and administrator rights etc, it wouldn't even let me change the lock screen.

I found a 4.3 stock ROM and installed that instead, everything went back to working fine. I gave the official update another go (this time over Kies) and this time it successfully upgraded to 4.4 without any of the problems. In fact it worked fine, installed an app to elt apps access the sd card and the battery life was noticeably better.

A couple of days later I was looking into putting Galaxy S5 features (like Ultra power saving mode) onto the S4 and found a mod which sounded perfect. I tried installing it via CWM Recovery and this is where the serious problems started.

currently it's back on 4.2, stock ROM. The phone takes significantly longer to start up than it used to and Wi-Fi won't work at all (I try toggling it but it just stays off). If I try and install a replacement ROM via ODIN it fails after a few seconds and the phone can no longer start up (Recovery doesn't work either, it throws up some Kies firmware initialisation error).

If I install a recovery via ODIN however it goes back to taking ages to startup and no Wi-Fi (though the rest of the phome seems okay and it let's me root).

I've rooted and installed ROMs a bunch of times on this phone and the S2 successfully, this is the first time it's gone properly wrong. Spent hours looking for answers but no joy, done the whole clearing cache etc. Does anyone have any ideas what's going on/how to fix it?

 

I did a backup before I did the firmware upgrade from 4.2 to 4.4. I've used it to restore my phone back to how it was (aside from the wi-fi and long startup time). Didn't do one before modding the 4.4 rom though

 

The first time when I upgraded to 4.4 and it had the wi-fi problem, I installed 4.3 (I9505XXUEMK8) and that sorted it, so that's the one I've been trying to do. Also tried a 4.4 stock ROM but no joy either. Both Stock ROMs yeah.

Guess it can't hurt. is there a ROM(s) you'd suggest? Ideally something close to TouchWiz where I can keep the S4 stuff like multi window and air controls, with some of the extra stuff from the S5 like ultra low power saving mode and water proofing (joking about the last one ). That's off the top of my head, if there are some kick ass ROMs then I'm open minded

 

AHA! Fixed it!

Took your advice and checked out some ROMs, specifically DjeMBeY ROM. Not only did it work on the first try, but because my phone had reverted (keeping all its settings) it wrapped 4.4 around everything I'd set up before doing all this messing about.

The Wi-fi works fine and startup time is normal again. No idea if it'll let me install the stock ROMs again but it doesn't matter now.

Short version, everything is working as it should, including the KK firmware. As a nice bonus it's pre-rooted and the bloatware is gone.