Hello Kostya Kostyushko,
* Run Odin flash tool,
* put your phone in to download mode (vol down/home/power button) and connect to PC via USB
* Tick re-partition box on odin tool
* Click PDA and select your stock official Samsung ROM
* Flash and wait for reboot
You have to find Correct ROM and Odin tool for S5 Active.
Note : All data will be lost on your user data partition as you re partition the ROM & . Flash your device at your own risk.
Hope this answer help you to fix your dead S5
Cheers!