Sony has released Marshmallow update for its Xperia Z3 D6603 and also for Xperia Z2 and Z3 compact devices. This Marshmallow firmware is official with 23.5.A.0.570 build number. Many of the Z3 users may receive the update (OTA) but those of you who are still waiting for update can install it manually by following our simple step by step guide.
This guide is only and only for Sony Xperia Z3 D6603 so Do Not try this on any other device or Z3 variants otherwise you will result in bricking your device. Go to settings > About phone option to check model number.
* If you are flashing a Custom ROM or official firmware always create a complete backup of your important data first. Backup your Contacts, Apps, Text data, Call logs and other photos and multimedia files.
* Download and install Sony Flash tool to flash this firmware.
* Make sure your Z3 has charging at least 70% to do the flashing safely.
* Enable USB debugging mode, in Settings under about phone option tap build number for seven times to Enable developers options and then Enable USB debugging there.
Download the file below
Xperia Z3 D6603 Android Marshmallow FTF file | link
Flashing process to Update Xperia Z3 to Marshmallow
1. Download the firmware file and then copy the file in Flashtool > firmware folder.
2. Now launch firmware flash tool.exe software on PC.
3. On the left top corner of the screen you’ll see lightning button tap it and select Flash mode.
4. Here look out for FTF firmware file, you’ve recently downloaded and select it.
5. Now from the right side Wipe data and also Clear the Cache and App log then click OK to load the file.
6. Soon you will see a pop up asking you to connect the phone after turning it off and constantly pressing the volume down key.
7. Your phone will be detected now and Flashing will begin.
NOTE: Do Not release the Volume down key until the flashing is done.
That’s all, your device will reboot in normal mode and Marshmallow would be running on your Xperia Z3.