Ok, thanks. As i thought, looks like something wrong with this script, or with my installation of libreelec. I always get some errors when executing it.
Code
Traceback (most recent call last):
File "/storage/wakeonlan.py", line 103, in <module>
main()
File "/storage/wakeonlan.py", line 99, in main
send_magic_packet(*args.macs, ip_address=args.i, port=args.p)
File "/storage/wakeonlan.py", line 60, in send_magic_packet
packets = [create_magic_packet(mac) for mac in macs]
File "/storage/wakeonlan.py", line 34, in create_magic_packet
return bytes.fromhex("F" * 12 + macaddress * 16)
AttributeError: type object 'str' has no attribute 'fromhex'
UPD: I was download script from developer's site, replace it in /storage and now everything works fine.