[Xperia Z2 Q&A, Help & Troubleshooting] Nevexus:
Hi, at first, sorry for my english, I'm still learning, please understand!

I have pretty big problem with my Xperia Z2 D6503. I bought this phone with custom rom, Resurrection Remix OS (i don't remember the version, but I think that's not important). I tried to enter custom recovery to install newer OS, but my phone vibrates three times only, with no other results. I decided to stay with this rom, but first i tried to set the factory settings. Now, after reebot, i saw unexpected TWRP menu, so I decided to install new rom. I installed AICP based on Android 8.1 and OpenGapps for that version of OS. Everything worked fine, but I realised, that i can't use Google Pay with rooted/customed device, so I decided to install the stock rom for my Xperia. I used Flashtool, installed every driver succesfully, but I couldn't install the rom. I tried few different stock roms, but it doesnt helped. I decided to re-unlock bootloader, just to be sure, because i didn't know anything about past of this phone. I choosen right version of my device and tried to unlock bootloader. Suprisingly it didn't asked me for the unlock key, it filled the gap itself. I decided to click next, and after that I realised, that I made a mistake. My phone can't boot up now, there is no Sony logo anymore, after pressing the power button it only vibrates once. I tried to install recovery, install stock rom again and re-unlock bootloader again. Nothg helped. I will give you logs from this actions bellow. I really need help, because I don't know what to do anymore. If someone can help me, then please, do this. Thank you for every response to my post!

Bootloader unlock:

18/049/2018 19:49:50 - INFO - Flashtool Version 0.9.24.4 built on 01-02-2018 22:15:00

18/049/2018 19:49:50 - INFO - Searching for a web proxy

18/049/2018 19:49:50 - INFO - No proxy found, using direct connection

18/049/2018 19:49:50 - INFO - Syncing devices from github

18/049/2018 19:49:51 - INFO - Opening devices repository.

18/049/2018 19:49:51 - INFO - Scanning devices folder for changes.

18/049/2018 19:49:59 - INFO - Pulling changes from github.

18/049/2018 19:49:59 - INFO - Devices sync finished.

18/050/2018 19:50:00 - INFO - Loading devices database

18/050/2018 19:50:00 - INFO - Loaded 106 devices

18/050/2018 19:50:00 - INFO - Starting phone detection

18/050/2018 19:50:05 - INFO - Device connected in flash mode

18/050/2018 19:50:20 - INFO - Device disconnected

18/050/2018 19:50:30 - INFO - Selected Bundle for Sony Xperia Z2(D6503). FW release : 23.5.A.1.291. Customization : Customized CE1

18/050/2018 19:50:30 - INFO - Preparing files for flashing

18/050/2018 19:50:45 - INFO - Please connect your device into flashmode.

18/050/2018 19:50:52 - INFO - Using Gordon gate drivers version 3.2.0.0

18/050/2018 19:50:52 - INFO - Opening device for R/W

18/050/2018 19:50:52 - INFO - Device ready for R/W.

18/050/2018 19:50:52 - INFO - Reading device information

18/050/2018 19:50:52 - INFO - Phone ready for flashmode operations.

18/050/2018 19:50:52 - INFO - Opening TA partition 2

18/050/2018 19:50:52 - INFO - Current device : Unknown: Jul 24 2016/19:28:59 - BH900AGD16 - Unknown: Jul 24 2016/19:28:59 - Unknown: Jul 24 2016/19:28:59 - GENERIC_23.5.A.1.291

18/050/2018 19:50:52 - INFO - Closing TA partition

18/050/2018 19:50:52 - ERROR - The bundle does not match the connected device

18/050/2018 19:50:52 - INFO - Ending flash session

18/050/2018 19:50:53 - INFO - Device disconnected

18/050/2018 19:50:58 - INFO - Device connected in flash mode

18/051/2018 19:51:26 - INFO - Device disconnected

18/051/2018 19:51:40 - INFO - Please connect your device into flashmode.

18/051/2018 19:51:46 - INFO - Using Gordon gate drivers version 3.2.0.0

18/051/2018 19:51:46 - INFO - Opening device for R/W

18/051/2018 19:51:46 - INFO - Device ready for R/W.

18/051/2018 19:51:46 - INFO - Reading device information

18/051/2018 19:51:46 - INFO - Phone ready for flashmode operations.

18/051/2018 19:51:46 - INFO - Opening TA partition 2

18/051/2018 19:51:47 - INFO - Current device : Unknown: Jul 24 2016/19:28:59 - BH900AGD16 - Unknown: Jul 24 2016/19:28:59 - Unknown: Jul 24 2016/19:28:59 - GENERIC_23.5.A.1.291

18/051/2018 19:51:47 - INFO - Closing TA partition

18/051/2018 19:51:47 - INFO - No loader in the bundle. Searching for one

18/051/2018 19:51:50 - INFO - Processing loader.sin

18/051/2018 19:51:50 - INFO - Checking header

18/051/2018 19:51:50 - INFO - Flashing data

18/051/2018 19:51:50 - INFO - Loader : S1_Root_9c84 - Version : MSM8974AB_7 / Boot version : S1_Boot_MSM8974AB_LA2.0.1_43-A / Bootloader status : ROOTABLE

18/051/2018 19:51:50 - INFO - Max packet size set to 512K

18/051/2018 19:51:50 - INFO - Opening TA partition 2

18/051/2018 19:51:50 - INFO - Start Reading unit 00 00 08 B2

18/051/2018 19:51:50 - WARN - ERR_SEVERITY="MINOR";ERR_CODE="0025";ERR_DYNAMIC="00000000";

Rom Install:

18/049/2018 19:49:50 - INFO - Flashtool Version 0.9.24.4 built on 01-02-2018 22:15:00

18/049/2018 19:49:50 - INFO - Searching for a web proxy

18/049/2018 19:49:50 - INFO - No proxy found, using direct connection

18/049/2018 19:49:50 - INFO - Syncing devices from github

18/049/2018 19:49:51 - INFO - Opening devices repository.

18/049/2018 19:49:51 - INFO - Scanning devices folder for changes.

18/049/2018 19:49:59 - INFO - Pulling changes from github.

18/049/2018 19:49:59 - INFO - Devices sync finished.

18/050/2018 19:50:00 - INFO - Loading devices database

18/050/2018 19:50:00 - INFO - Loaded 106 devices

18/050/2018 19:50:00 - INFO - Starting phone detection

18/050/2018 19:50:05 - INFO - Device connected in flash mode

18/050/2018 19:50:20 - INFO - Device disconnected

18/050/2018 19:50:30 - INFO - Selected Bundle for Sony Xperia Z2(D6503). FW release : 23.5.A.1.291. Customization : Customized CE1

18/050/2018 19:50:30 - INFO - Preparing files for flashing

18/050/2018 19:50:45 - INFO - Please connect your device into flashmode.

18/050/2018 19:50:52 - INFO - Using Gordon gate drivers version 3.2.0.0

18/050/2018 19:50:52 - INFO - Opening device for R/W

18/050/2018 19:50:52 - INFO - Device ready for R/W.

18/050/2018 19:50:52 - INFO - Reading device information

18/050/2018 19:50:52 - INFO - Phone ready for flashmode operations.

18/050/2018 19:50:52 - INFO - Opening TA partition 2

18/050/2018 19:50:52 - INFO - Current device : Unknown: Jul 24 2016/19:28:59 - BH900AGD16 - Unknown: Jul 24 2016/19:28:59 - Unknown: Jul 24 2016/19:28:59 - GENERIC_23.5.A.1.291

18/050/2018 19:50:52 - INFO - Closing TA partition

18/050/2018 19:50:52 - ERROR - The bundle does not match the connected device

18/050/2018 19:50:52 - INFO - Ending flash session

18/050/2018 19:50:53 - INFO - Device disconnected

18/050/2018 19:50:58 - INFO - Device connected in flash mode

Recovery install:

C:\Program Files (x86)\Minimal ADB and Fastboot>adb devices

List of devices attached

* daemon not running; starting now at tcp:5037

* daemon started successfully

C:\Program Files (x86)\Minimal ADB and Fastboot>fastboot flash recovery recovery.img

target didn't report max-download-size

sending 'recovery' (11570 KB)...

OKAY [ 0.372s]

writing 'recovery'...

FAILED (remote: Command not allowed)

finished. total time: 0.383s