[Xperia Z2 Q&A, Help & Troubleshooting] GalosSide:
This may related to kernel problem. I think I used the wrong one.(Fast boot is accessible)

today i tried to install lollipop on my D6503 Z2 device running 17.xxxxxx (I cant remember and i cant turn my phone on now)

i downloaded the file from this thread http://xdaforums.com/xperia-z2/development/stock-d6503-23-1-0-690-bal-rooted-t3057150

however, i cant flash the zip file since i cannot get in to recovery mode. (when ever i try to reboot into recovery mode it just boot into normal stock rom) So i tried installing TWRP from the play store app "TWRP Manager" https://play.google.com/store/apps/details?id=com.jmz.soft.twrpmanager&hl=en but it failed. I remember it said something like "the installation has failed. Either you have already install custom recovery or there might be some other problems. Do you want to reboot in recovery mode?" I clicked "yes" then it booted into stock rom again. After failing I went into TWRP website and manually download the latest version of TWRO 2.8.6.0 on this website http://dl.twrp.me/sirius/ and proceed to download flashtool form www.flashtool.net/ .

I conected my device and install dual boot recovery "Z2-lockeddualrecovery2.8.3-RELEASE.installer". I choose no. 3 first (which nothing happened) and then i choose no. 1. Its said successful. I tried to reboot again which didn't change anything.

Then I opened the flashtool i downloaded and get into fastboot mode( since flash mode cant flash the img file for me. or I just don't know how to do it). In fast boot option I clicked "reboot into fastboot mode via ADB" every went fine I got the blue light with black screen. Then I clicked "select Kernel to Flash" which is my TWRP recovery. After it is done, I tried to reboot back to stock however after the sony logo is shown the screen went dark and I couldn't do anything beside pressing volume up and power to force shut down. I rebooted and nothing changes.

In short

-I tried to install lollipop pre rooted on my Z2

-Couldn't instal. I can't reboot into recovery mode

-try to manually install TWRP by downloading from its website and flash in fastboot mode (i choose "select Kernel to Flash")

-Now I cannot boot my device back to stock. After the sony is shown, the screen went black. I need to forced shutdown.

-Just realized that my kernel version changed to 3.4.0cyanogenmod

-I probably flashed the wrong kernel

-I cannot get into recovery mode

-i did do a TWRP back up

Btw here is my log when trying to flash the TWRP

28/052/2015 00:52:45 - INFO - For 2011 devices line, be sure you are not in MTP mode

28/052/2015 00:52:46 - INFO - Device connected with USB debugging on

28/052/2015 00:52:46 - INFO - Connected device : Sony Xperia Z2

28/052/2015 00:52:46 - INFO - Installed version of busybox : BusyBox v1.22.1-Stericson (2014-01-25 17:27:18 CET) multi-call binary.

28/052/2015 00:52:46 - INFO - Android version : 4.4.2 /

kernel version : 3.4.0-perf-g35f9635

/ Build number : 17.1.2.A.0.314

28/052/2015 00:52:46 - INFO - Checking root access

28/052/2015 00:52:47 - INFO - Root Access Allowed

28/052/2015 00:52:47 - INFO - Installing toolbox to device...

28/052/2015 00:52:47 - INFO - Pushing C:\Flashtool\custom\root\ftkit.tar to /data/local/tmp

28/052/2015 00:52:48 - INFO - Running installftkit as root thru sysrun

28/054/2015 00:54:31 - INFO - Selected null

28/054/2015 00:54:31 - INFO - Flash canceled

28/054/2015 00:54:38 - INFO - Launching Service Menu. Plese check on your phone.

28/055/2015 00:55:53 - INFO - Device Status: ADB mode

28/056/2015 00:56:19 - ERROR - This action can only be done in fastboot mode

28/056/2015 00:56:32 - INFO - Please wait device is rebooting into fastboot mode (via ADB)

28/056/2015 00:56:32 - INFO - Device will soon enter fastboot mode

28/056/2015 00:56:33 - INFO - Device disconnected

28/056/2015 00:56:35 - INFO - Device connected in fastboot mode

28/057/2015 00:57:00 - INFO - Selected kernel (boot.img or kernel.sin): D:\Downloads\twrp-2.8.6.0-sirius.img

28/057/2015 00:57:00 - INFO - Flashing selected kernel

28/057/2015 00:57:02 - INFO - sending 'boot' (11928 KB)...

28/057/2015 00:57:02 - INFO - OKAY [ 0.397s]

28/057/2015 00:57:02 - INFO - writing 'boot'...

28/057/2015 00:57:02 - INFO - OKAY [ 0.864s]

28/057/2015 00:57:02 - INFO - finished. total time: 1.261s

28/057/2015 00:57:02 - INFO - FASTBOOT Output:

sending 'boot' (11928 KB)...

OKAY [ 0.397s]

writing 'boot'...

OKAY [ 0.864s]

finished. total time: 1.261s

28/057/2015 00:57:02 - INFO - Please check the log before rebooting into system

28/057/2015 00:57:18 - INFO - Device Status: FASTBOOT mode

28/058/2015 00:58:13 - INFO - Device will now exit fastboot mode and start booting into system

28/058/2015 00:58:13 - INFO - Device disconnected

28/059/2015 00:59:11 - ERROR - This action can only be done in fastboot mode

28/059/2015 00:59:17 - INFO - Device Status: NOT FOUND

28/003/2015 01:03:27 - INFO - Device connected with USB debugging on

28/003/2015 01:03:27 - ERROR - Cannot identify your device.

28/003/2015 01:03:27 - INFO - Selecting from user input

28/004/2015 01:04:01 - INFO - Connected device : D65XX

28/004/2015 01:04:02 - INFO - Installed version of busybox : BusyBox v1.22.1 bionic (2015-03-25 05:26 +0000) multi-call binary.

28/004/2015 01:04:02 - INFO - Android version : / kernel version :

3.4.0cyanogenmod-g449fd42

/ Build number :

28/004/2015 01:04:02 - INFO - Phone in recovery mode

28/004/2015 01:04:02 - INFO - Root Access Allowed

I'm going to go sleep now. Will try to wake up early as possible to reply.