[Sony Xperia XZ2 Compact Guides, News, & Discussion] ferluna18:
Android 10 last build that came out this march solved lots of problems but still had one that was unforgivable for me, the low volume of voice recording while using whatsapp, telegram and messenger, so I looked for a way to make a downgrade to android 9 and without having to unlock bootloader and I found one that worked and want to share with you:

Requirements/materials:

-Sony drivers for your phone (I got them by installing latest version of Sony PC companion)

-New flasher v20 (original thread: https://xdaforums.com/crossdevice-dev/sony/progress-newflasher-xperia-command-line-t3619426)

-XperiFirm (to download Android 9 firmware.) (you can get it by downloading flashtool or from the original post:

https://xdaforums.com/crossdevice-dev/sony/pc-xperifirm-xperia-firmware-downloader-t2834142)

-flashtool (I used 0.9.27.0 version) https://mega.nz/#!g24hXIQa!L22-invd46Onx7pzAEf0C4tkrAe87AR1JftRni8G6rA

Instructions:

1-open Xperifirm to download your firmware:

look your phone on the left side, then your specific model (in my case it was H8314, if you dont know your model check in your phone settings) once you selected your phone Xperifirm will show a list of firmwares on the right side, select one of the builds with the number 52.0.A.11.32 on it if you want the latest build of Android 9. In my case 52.0.A.11.32/R3B from chile worked (i´m from mexico). Once you have selected your build then click on the square button that is below of "availanle firmware" and a windows will open and show you two options to download the files, you hit the "Download" button. then another window will open and the program will start downloading your firmware.

Once it`s downloaded you should get this files:

[IMG="folder example"]http://s2.subirimagenes.com/imagen/previo/thump_9919850sin-ttulo.png[/IMG]

except the folder that says "Decrypted", I will explain about such folder later.

2-Open Flashtool and Decrypt the firmware files

2.1-select the next options on the menu: Tools>Bundles>FILESET Decrypt

[IMG="stepd flashtool"]http://s2.subirimagenes.com/imagen/previo/thump_9919852sin-ttulo.png[/IMG]

2.2-look for the path of the folder in which you downloaded your firmware, and then move to the right the three files you have on the left and click on convert.

[IMG="flashtool steps"]http://s2.subirimagenes.com/imagen/previo/thump_9919853sin-ttulo.png[/IMG]

It will take around five minutes to convert all the files, Once flashtool is done with that, it will ask you to create a bundle, click on "cancel" to close the window. So now if you look at the folder where you have the firmware files you got a new folder called "Decrypted" that I mentioned and that you saw in the picture above in step 1, if you open it, it will look like this:

[IMG="folder example"]http://s2.subirimagenes.com/imagen/previo/thump_9919876sin-ttulo.png[/IMG]

with a folder called "boot" and another called "partition", and some files as well.

3-Download (if you have not) and extract New flasher v20 in a new folder

(link posted above in the "Requirements/materials" section)

You should get this files:

[IMG="newflasher v20 files sample"]http://s2.subirimagenes.com/imagen/previo/thump_9919879sin-ttulo.png[/IMG]

4-Preparing the firmware files:

4.1-open the firmware folder, select and delete all of the .ta files in the main folder.

[IMG="folder sample"]http://s2.subirimagenes.com/imagen/previo/thump_9919882sin-ttulo.png[/IMG]

4.2-Now open the ‘boot’ folder within the main firmware folder. There is one .ta file in here called ‘Apollo_XBootConfig_MiscTA‘ that you also need to delete.

(Note: something else instead of "apollo" could be in the name of the file depending on your phone model)

[IMG="folder sample"]http://s2.subirimagenes.com/imagen/previo/thump_9919883sin-ttulo.png[/IMG]

4.3-Now the final step in preparing your firmware, is to copy the entire contents of the firmware folder to the Newflasher folder.

[IMG="folder sample"]http://s2.subirimagenes.com/imagen/previo/thump_9919887sin-ttulo.png[/IMG]

Once complete, your Newflasher folder should look like something below. The highlighted files are those copied across from your firmware folder.

5-Flash Xperia firmware

If you’ve reached this stage, then that’s the hardest part done. This next section involves the process of actually flashing your Sony Xperia device.

5.1-Connect your Sony Xperia device. Make sure the device is powered off and then hold the ‘volume down’ button whilst connecting the USB cable. You will see the led of your phone turns on and stays on, (that means it entered into flashmode)

5.2-Double click the ‘newflasher’ application as highlighted below.

5.3-A Windows command prompt will now open. It will ask you if you want to perform an optional step (if you need a gordongate flash drive) Type ‘n’ for no and press Enter.

[IMG="newflasher sample for step 5.2 and 5.3"]http://s2.subirimagenes.com/imagen/previo/thump_9919893sin-ttulo.png[/IMG]

5.4-newflasher will will ask you again if you want to perform an optional step, (dump trim area) Type ‘n’ for no and press Enter.

5.5-newflasher will ask you if you want to perform another optional step (flash bootloader,bluetooth,dsp,modem,rdimage to booth a,b slots)Type "n" for no and press Enter.

5.6-Your Sony Xperia device will now begin to flash new firmware.

You will see some files going through during the flashing

5.7-newflasher will ask you if you want to perform another optional step(flash persist partition).Type "n" for no and press Enter.

You will see some other files going through the screen

6- Once complete, you will receive a message that “You can disconnect your device when you close newflasher.exe“.

[IMG="neflasher sample for step 5.6"]http://www.xperiablog.net/wp-content/uploads/2018/01/Sony-Xperia-Newflasher-Guide_13-640x399.png[/IMG]

Congratulations, your Sony Xperia device has now been successfully flashed to new firmware.

7-Disconnect your Xperia device and power on the handset. Don’t worry if it takes a while for the handset to boot, this is to be expected. To confirm that you have upgraded the phone software, click on ‘Settings > About phone’, which will reveal your new Android version and firmware build number.

Final Note:

-some parts of this guide were obtained from here: https://www.xperiablog.net/2018/01/...-firmware-for-xperia-xz-premium-xz1-and-more/