Sony Xperia Z1 won't start up again! As you may know, you have to backup the TA-partition before you put a custom ROM on the Sony Xperia Z1. I've backupped the partition with this .bat file:

http://forum.xda-developers.com/showthread.php?t=2292598&amp;highlight=ta

I've rooted my Z1 succesfully and flashed a custom ROM on it (PACMAN-ROM). 
Right after that I've tried to restore the TA-partition with that same program (.bat file), because the camera didn't work well (the camera wouldn't focus and the flash wasn't working). 

Everything went well untill the program asked me to reboot the device.
It shutted down and did not boot again.

I've tried to put a boot image (adv-stock-v3.img) on it again with CMD (sdk, platform-tools, ya know) while the Z1 is in fastboot-modus. 

But I keep getting the "FAILED "-error.

C:\Users\Teake\Desktop\adt-bundle-windows-x86-20130917\sdk\platform-tools>fastbo
ot flash boot adv-stock-v3.img
sending 'boot' (13254 KB)...
OKAY [  0.454s]
writing 'boot'...
FAILED 
finished. total time: 0.458s

How can I get my boot image working again on my Z1?
Try to re-install ROM on your device (here's the newest firmware), that usually helps in similar situations. 

If your phone will be still broken that means you have damaged bootloader (boot partition) - then try to re-install boot partition (you can find instructions in internet).

At most you can give your phone to service and tell that your phone has been broken during an update. Repair will be free if you have warranty.