Flashing my Sony Z3 into CarbonRom – as of September 2018
Links
Installation
Receive an official Sony code to unlock your Z3 Bootloader. Unlocking will remove certain DRM keys so some features will no longer be available.
Backup your data. If you have your phone encrypted ( like I did ) there is no way to unencrypt the phone, you have to backup manually.
Install TWRP version 3.2 from March, 28th . This version has to be used to install version 6.1. Do not attempt to install GAPPS immediately after. You first have to downgrade to TWRP version 3.1 from October 2nd , the version 3.2 from March, 28th has unzip not included and GAPPS refuses to install. Both TWRP can be installed using fastboot along with the FOTAKernel option.
Wipe your phone AFTER backing up important data – or if needed – the stock ROM.
Now install CarbonRom and optionally MindTheGapps.
Reboot – done!
It took me 5 minutes to unlock the phone. A new install is performed within 30 seconds. Most time I spent figuring the shortcomings of TWRP 3.2 with the zipped installation packages. The CarbonRom installation version 5.1 worked with any TWRP, but Gapps add-on worked only with TWRP 3.1. TWRP3.2 has to be used for CarbonRom 6.1
I assume you are familiar with fastboot and adb. On Linux, these packages are readily available. Also note, that fastboot 26 or lower has to be used, the newer version do not seem to work properly.
I read something about to upgrade Sony's Bootloader using EMMA before flashing. However I did not run into problems not doing it.
Last worth mentioning: Booting up your phone into these modes
To use fastboot, press Volume UP ( next to Power button ) and plug in USB. The light turns blue after 2 seconds and the display remains dark.
To use TWRP, press first Volume DOWN (second to Power button) and then Power button, while still holding the Volume DOWN until you hear the snare. Display turns into blueish, and 5 seconds later the TWRP menu shows up.
And as always, have fun! CarbonRom 6.1 ( based on 8.1 Oreo ) works fantastic. It also addresses security problems with older Android versions, which is really important.