Is there a way to manually unlock the recovery? I've tried using DebugfsRoot_Generic_v2.3_Fixed_For_Padfone_4.0.4 and no luck. I'm a newb, so any hints much appreciated. Thanks!
Flash to different region firmware will wipe all your internal Apps/data but not external MicroSD card and risk with you warranty. So backup your data 1st.
Ask yourself, do you require root 1st?
1. If you don't need root, download CHT 9.20.2.14 (500MB) from asus web site. Go step 3.
2. If you need root download CHT 9.18.8.41 (475MB) from asus web site. Also take a look this firmware page. Download 9.18.8.41 to 9.20.1.22(CHT) & 9.20.1.22 to 9.20.2.14(CHT). Each of them less than 200MB
3. Save the zip(s) files to root of external SD Card. Downloaded zip from Asus web site do contain another zip file inside, make sure you have extract it.
4. Follow instruction install from recovery and install the full firmware 9.18 (for root) or 9.20 (non root). Once complete, do "wipe data/factory reset".
5. Restart the phone and the firmware install completed (if you don't need root)
6. Follow this page to root Padfone 9.18. The root method only works upto 9.18.
7. Once it has rooted, download OTA Rootkeeper from Play Store. Run it and protect root and click temp unroot. You should see the option to restore root but leave it for now.
8. Go to recovery again install 9.18.8.41 to 9.20.1.22 & 9.20.1.22 to 9.20.2.14. Once it done, go OTA Rootkeeper again click restore root.
9. Now you should be rooted with 9.20.2.14
Do not uninstall any apps while you rooted, just disable/freeze them. The updates might failed if you uninstall system apps.