[Xperia Z3 Compact Q&A, Help & Troubleshooting] Jake3:
Hey folks, I was following the how-to-root thread and made it to the very end without seeing any error messages. Unfortunately, when I booted up the device, it got stuck at the black 'sony' screen. So I dutifully scrolled up to step 1, as I have done plenty of times before, but I am having some trouble recovering my device. Also I feel like I should say, my previous 5.0.2 install was done using that thread with no issues, but I'd like to get up to 5.1.1 since I heard the memory management issues I've been having were improved.

FWs were acquired from the sticky firmware thread:

23.0.1.A.5.77 - Unbranded - USA (1289-7524)

23.4.A.0.546 - Unbranded - USA (1289-7524)

I have tried this on W7 and W10. I am using the OEM cable with a USB 2.0 port on my motherboard.

Here is my flashtools error:

21/054/2015 21:54:52 - INFO - Flashtool Version 0.9.19.3 built on 13-09-2015 17:00:00

21/054/2015 21:54:52 - INFO - Executing search strategies to find proxy selector

21/054/2015 21:54:52 - INFO - No proxy found for IE. Trying next one

21/054/2015 21:54:52 - INFO - Strategy firefox failed trying next one : No Firefox installation found

21/054/2015 21:54:52 - INFO - No proxy found for java. Trying next one

21/054/2015 21:54:52 - INFO - Syncing devices from github

21/054/2015 21:54:53 - INFO - Scanning devices folder for changes.

21/055/2015 21:55:01 - INFO - Pulling changes from github.

21/055/2015 21:55:01 - INFO - Devices sync finished.

21/055/2015 21:55:05 - INFO - Device disconnected

21/057/2015 21:57:00 - INFO - Selected Bundle for Sony Xperia Z3 Compact (D5803). FW release : 23.0.A.2.93. Customization : USA

21/057/2015 21:57:00 - INFO - Preparing files for flashing

21/057/2015 21:57:12 - INFO - Please connect your device into flashmode.

21/057/2015 21:57:19 - INFO - Device connected in flash mode

21/057/2015 21:57:19 - INFO - Opening device for R/W

21/057/2015 21:57:19 - INFO - Reading device information

21/057/2015 21:57:19 - INFO - Phone ready for flashmode operations.

21/057/2015 21:57:19 - INFO - Opening TA partition 2

21/057/2015 21:57:20 - INFO - Current device : Unknown: Apr 13 2015/13:21:35 - YT91127UXN - Unknown: Apr 13 2015/13:21:35 - 1285-6521_23.1.A.1.28 - Unknown: Apr 13 2015/13:21:35

21/057/2015 21:57:20 - INFO - Closing TA partition

21/057/2015 21:57:20 - INFO - Start Flashing

21/057/2015 21:57:20 - INFO - Processing loader.sin

21/057/2015 21:57:20 - INFO - Checking header

21/057/2015 21:57:20 - INFO - Flashing data

21/057/2015 21:57:20 - INFO - Loader : S1_Root_9c84 - Version : MSM8974AB_22 / Boot version : S1_Boot_MSM8974AC_LA3.0_52-2 / Bootloader status : ROOTABLE

21/057/2015 21:57:20 - INFO - Max packet size set to 512K

21/057/2015 21:57:20 - INFO - Parsing boot delivery

21/057/2015 21:57:20 - INFO - Ending flash session

21/057/2015 21:57:21 - ERROR -

21/057/2015 21:57:21 - ERROR - Error flashing. Aborted

21/057/2015 21:57:21 - INFO - Device connected in flash mode

21/057/2015 21:57:21 - INFO - Device disconnected

21/057/2015 21:57:24 - INFO - Device connected in flash mode

21/005/2015 22:05:21 - INFO - List of connected devices (Device Id) :

21/005/2015 22:05:21 - INFO - - USB\VID_0FCE&PID_ADDE\5&1E313DEC&0&4	Driver installed : true

21/005/2015 22:05:21 - INFO - List of ADB devices :

21/005/2015 22:05:21 - INFO - - none

21/005/2015 22:05:21 - INFO - List of fastboot devices :

21/005/2015 22:05:21 - INFO - - none

And I'm also having trouble with PC Companion's repair function:

Edit: I have heard on the grapevine that PC Companion does not download firmwares properly on Windows 10, so I threw W7 on my secondary hard drive. Sure enough, it downloaded just fine. If your PC companion is giving you "Unable to communicate with Sony Update Engine" and you are on W10, there's your problem.

UNFORTUNATELY, I am now getting "Sony Update Engine doesn't have software available for your device." I've taken it to the search engines and it seems the general idea is to use flashtool instead. Unfortunately, flashtool's behavior on W7 is completely identical to what I've gotten on W10.