lte firmware 41065 Vs 43818

[kjm]

I can run

import time, machine, network, socket, pycom, sys
lte=network.LTE(); pycom.heartbeat(False)
red=0x7f0000; orange=0xff5100; yellow=0x7f5100; green=0x007f00; blue=0x00007f; cyan=0x007f7f; magenta=0x7f007f; off=0x000000; white=0x7f7f7f

def _led(color): pycom.rgbled(color); time.sleep(.5); pycom.rgbled(off); time.sleep(.5); print('.', end=' ')

def _lte():
  print('lte attach', end=' '); lte.attach()
  while not lte.isattached(): _led(orange)
  print('lte connect', end=' '); lte.connect()
  while not lte.isconnected(): _led(yellow)


try:
  lte=network.LTE()
  if lte.isconnected(): lte.disconnect()
  r=lte.send_at_cmd('ati1'); r=r.split('\r\n'); print('lte firmware', r[2])
  _lte(); cycle=0
  while 1:
    print(); print('cycle', cycle)
    print('modem still connected?', lte.isconnected()); s=0; path=''; host='detectportal.firefox.com'
    t1=time.time(); addr=socket.getaddrinfo(host, 80)[0][-1]; t=time.time()-t1; print('dns in', t, 'sec,', addr)
    t1=time.time(); s=socket.socket()#; s.settimeout(9)
    s.connect(addr); s.send(bytes('GET /%s HTTP/1.0\r\nHost: %s\r\n\r\n' % (path, host), 'utf8'))
    l=s.readline(); t=time.time()-t1; s.close()
    l=l.split(None, 2); status = int(l[1]); print('srvr reply in', t, 'sec,', 'status code', status)
    for i in range (57): _led(green)
    cycle+=1
except Exception as e:
  sys.print_exception(e)
  if s: s.close()

on a gpy with CAT-M1 41065 modem firmware & it will go for thousands of cycles before ending in an OSError, but when I try it on a gpy with CAT-M1 43818 modem firmware

lte firmware LR5.1.1.0-43818
lte attach lte connect
cycle 0
modem still connected? True
dns in 0 sec, ('23.192.108.91', 80)
srvr reply in 0 sec, status code 200
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
cycle 1
modem still connected? True
dns in 1 sec, ('23.192.108.91', 80)
srvr reply in 0 sec, status code 200
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
cycle 2
modem still connected? True
dns in 0 sec, ('23.192.108.91', 80)
srvr reply in 0 sec, status code 200
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
cycle 3
modem still connected? True
dns in 1 sec, ('23.192.108.97', 80)
srvr reply in 0 sec, status code 200
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
cycle 4
modem still connected? True
Traceback (most recent call last):
  File "<stdin>", line 23, in <module>
OSError: [Errno 202] EAI_FAIL

it always crashes way sooner.

1. Does anyone have a 43818 GPY to confirm this behaviour please?
2. Can someone PLEASE tell me what I have to do to make this program reliable with 43818 modem firmware?