“There is a problem in the get_hostbyname method.”
I can confirm that.
“I managed to fix it and rebuild the micropython package,”
Can you please show how?
“but still other functions are missing or not working:
recv : is broken (i know it was solved in the 3rd update of the firmware but the fix is not in the repo) so I can’t have the DNS”
I can confirm that recv is still broken on 3rd firmware if the response is bigger than few bytes (the freechess.org Wiki example does abort always):
https://forums.raspberrypi.com/viewtopic.php?p=1978647#p1978647
Last, but not least, the inside module communication is not reliable 
>>> import forum
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "forum.py", line 7, in <module>
OSError: couldn't init nic esp8285 ,try again please
>>>