Cannot remove/rename/move build.prop, new insights

Question

I soft-bricked my Huawei G700 running Android 4.2.1 by editing a line in build.prop, specifically this one.

ro.config.hwtheme=1

to

ro.config.hwtheme=0

My phone didn't like that apparently. It supposedly fixes the Xposed framework limited mode bug.

Now, I can boot into recovery and restore my phone to factory reset, but this is not something I'm very willing to do unless everything else fails. In recovery, I'm unable to use ADB to connect to my phone, I can wipe things, reset and apply patches, but that's it.

Now, if I boot my phone and it gets stuck in the boot animation, I can suddenly use adb fine. Hurray right? Just restore build.prop.bak.

Yeah, not. Nothing works.

chmod 777 build.prop -> Read-only
su chmod 777 build.prop -> nothing happens
su mv build.prop build.prop.back -> nothing happens
su -> nothing happens
su -s -> chainfire information ( from SuperSU )
mount -o remount,rw /system /system -> not permitted
su mount -o remount,rw /system /system -> nothing happens

All these commands were run in /system

Can someone help me out with this? I don't want to have to use my last resort.

So, what's changed?

Well, if I boot normally, the phone functions fine in the background as if I didn't enter a PIN code. It requests an IP address from my router and connects fine, but something like web.whatsapp.com won't work.

Volume Down + Power boots into... Fastboot? Well, kinda, not really. It just says two things

NEW:RISK
OLD:RISK

What I found on Google isn't much and it isn't promising. No solutions.

When I boot the device, fastboot does detect the device as an mt6589 with the boot image being secure.

SPFlasher does not work, it fails to detect my device in any mode and will not flash anything.

I tried updating from recovery with a zip file but everything fails. After some googling, it appears to be likely that the zip file has to be signed by Huawei themselves.

I tried installing adbd insecure v2 from Chainfire, but I have NO idea how to enable this from adb. I can't enable this the normal way.

So, here's what I thought. Can't I call the Huawei theme manually from the adb shell? For that, I need someone else who can check this.

If that doesn't work, do you guys have any other ideas?

If none of those work, I could ask for an OEM key and flash another recovery, but that seems like a terrible idea as I have no GUI.

Then there are three things left, sending it to Huawei / dropping it at a local repair shack, neither appeals as they are costly and mean I'll lose my phone for a while.

Or, and that's the thing I really don't want to, buy another phone. I'm content with the phone itself, curiosity merely killed it.

**I think I can't edit it because it's in use, not because I lack access as can be seen here **

Cheered too early.