[Xperia Z2 Q&A, Help & Troubleshooting] JJD809:
Hi guys,

I have a bit of a problem, but either I'm not searching correctly or I just cannot find the topic that addresses my issue.

I have a Z2 (D6503), still on Android v5.1.1 (23.4.A.1.264). It is rooted, have a locked bootloader and Z2-lockeddualrecovery2.8.26-RELEASE.combined.zip installed.

I want to upgrade to MM (23.5.A.1.291) and maintain root. I have an idea in mind of what I want to do but want to know if it will work or not; is it the right way to do it? If not, then how can I upgrade and keep root?

I also have a Xperia Z3 Compact Tablet that I successfully upgraded to Marshmallow SGP621_23.5.A.1.291 this morning using steps as followed on their forums. My plan is upgrade my Z2 using the same procedure, but with one slight addition (if needed)

In brief (not ;) ), the Z3 Compact Tablet was upgraded as follows:

Step 1. Downloaded latest version of choice using XperiFirm v5. (I prefer the generic Swiss version)

Step 2. Created ftf using Flashtool

Step 3. Created flashable zip file using PRF Creator v1.3 but with slight variation in that the normal SuperSU zip file is not used at all;

Step 3.a. In FTF File field: The ftf as created in step 2

Step 3.b. In SuperSU Zip field: dummy_flashable.zip

Step 3.c. In Recovery Zip field: RecRootV4_combined.zip

Step 3.d. Included (ticked) options: Kernel, FOTAKernel, Modem, LTALabel and Sign Zip

No Extra Files were added and Create was clicked to create the new zip file.

Step 4. Next step was to copy this new zip file as well as the RecRootV4_combined.zip to the SD card.

Step 5. Rebooted into TWRP recovery (must be TWRP, not any other) and then went to the Wipe - advance wipe option and selected to wipe only the Dalvik Cache, Cache and System.

Step 6. Once done, don't reboot but go back to the main menu and then select to install/flash the pre-rooted zip file as created with PRF Creator. Once this install is done, again, don't reboot but select to install/flash the RecRootV4_combined.zip file.

Step 7. Once this is done, the phone can be rebooted. Once the phone is done running the upgrade setup and you can access, you will get a prompt to upgrade Google Play Services. Once this is done, you then simply search for SuperSu and install and then update binaries and reboot. And that's that...

After this the tablet was on MM, maintained all previously installed apps,settings and data and most importantly; maintained root. I want to do the same with my Z2 but with one addition. At step 6 above I want to add another zip file to install called Z2-6.0.1_570_bootloop_fix.zip (which I also copied onto the SD card in Step 4) and then proceed with Step 7

I found the Z2-6.0.1_570_bootloop_fix.zip somewhere on the Z2 forums during my searches. Not sure if this is even neede for my situation or not.

I'm also aware that there's a RICDefeat.zip in circulation but this was never called for, or mentioned when upgrading the Z3 tablet so don't know if this is needed here with the Z2 or not.

If this is a workable solution I will add the dummy_flashable.zip, RecRootV4_combined.zip and Z2-6.0.1_570_bootloop_fix.zip files if so requested.

Thank you for reading all the way to this point! Any advice, suggestions, confirmations or warnings will be greatly appreciated.