So after trying to get swap memory working, I somehow managed to break it. After flashing stock ROM with Odin, efs/ is empty and boot is stuck on Samsung logo. I've tried a few other stock roms and they do the same or just get stuck on a boot loop. Both recovery and download mode work fine. I've also tried custom roms, they don't even load to boot animation and data/cache wipes didn't help.
Anything else I can try before sending it to maintenance?