[MeMO Pad 7 Q&A, Help & Troubleshooting] g3k:
My 191 duel!

I've done a lot of nasty things after 191 update and hopefully I could not brick the tablet (yet:))

My lessons learned:

* Yes. Root stays. Both Super SU and RootZenphone 1.4.6.4r had the survival mode active before update.

* You touch the rom files once, you can't update to 191. OTA or zip file in storage doesn't matter. Both methods stop with error and boot to 182 again.

* Once you fail during OTA update, you won't be offered 191. anymore. Only method is sideload update.zip in that case. But 182 full package must be flashed before update.zip to avoid integrity check error.

* At present, no downgrade is possible to 182. You go to 191 and you stay there until Asus releases a full package. Waiting...

* Full packages are automatically detected and used during boot. Recovery mode is not necessary. No matter where they are, be it internal storage or micro SD card, they are detected. I have even renamed and changed the extension. They were still detected under names like update.zipxx !!. But of course 182 package will be ignored if you're on 191 already. Downgrades are not offered...

* Titanium backup 6.2.0 still does a good job but it's a little harder than before, especially embedding updates of system apps back to the rom is tricky. I've gone too courageous to force this process at all costs and had to risk many resets. But it's ok at the end for me.

* I had once a Kit Kat, booting without keyboard, without any file manager. It was practically a booting brick without tools. APK installation with ADB saved me! Learn about ADB, you'll never regret it.

* I could not install any apk as system app via adb but installing as user app is possible. Kit Kat defends well here. However for the keyboard.APK, user app is ok to start recovering, hopefully. I've converted it to a system app later on.

* Google Apps are still a headache. Every time you mess with any system app, Google Play Services is ready to hang! But I've found why... Looks like it's an auto-downgrade issue.

* G.P.Services comes as v5.0.xxx first and gets a hidden auto-update by the OS to 6.1.blablabla without notice. Then every time you mess with rom files it automatically reverts back to 5.0, forgets about its own update and starts to give error on next boot. And of course, other Google Apps expect the new one. My workaround was to backup 6.1 with Titanium, as soon as it's available after auto update and restore it whenever the error appears, in offline mode (approx 36MB to download each time looked insane to me). And finally I've succeded to push it definitively into the rom. No more 5.0 to revert to, anywhere in my device now. The only persisting pb was Google Partner Setup which still kept hanging after boot. I finally decided to uninstall it! No app, no error, simply :) Gpartnersetup is not necessary at all to me.

Now I have a stable 191 version, booting without errors and all Gmail, G+, YouTube latest versions working, also all Asus bloatware updated and working. They are all user apps now and i can easily uninstall them quickly. I'd never understood why they are part of the rom package and I won't try to put them back in.

Last word: You can trim the 191 rom too, a lot, to your taste of simplicity. Please note that in case you decide to make a factory reset, anything you have ripped out before, will not be reinstalled. Should we care about that? No, as long as they are installable from apk's. BUT DON'T FORGET TO KEEP ALL APK FILES OF THE CRAP APPS YOU DECIDE TO TRIM...

Good digging to all.