modem-config-dump: Move config to /run and improve failure handling

BugzID: 56305

recipes-connectivity/modem-config-dump/files/modem-config-dump.py

@@ -4,7 +4,7 @@ import serial
 import os
 import time
 
-CONF_PATH = '/tmp/config/'
+CONF_PATH = '/run/modem'
 ser = serial.Serial('/dev/ttyACM0', 115200, timeout=0.5)
 while True:
     try:
@@ -15,7 +15,7 @@ while True:
 
 
 os.makedirs(CONF_PATH, exist_ok=True)
-config_file = open(CONF_PATH + '/ublox-tobyl2.conf', 'w')
+config_file = open(CONF_PATH + '/modem-at.config', 'w')
 
 def read_config(cmd, label=''):
     while True:
@@ -24,14 +24,14 @@ def read_config(cmd, label=''):
             ser.write(cmd)
             ser.write(b'\r')
             s = ser.read_until(b'OK')
+            if(len(s.decode('utf-8')) < 4): # Avoid empty response just after reset
+                continue
             break
         except Exception as e:
             print("Exception : " + str(e))
             time.sleep(1)
             continue
         
-    #if(len(s.decode('utf-8') < 1)):
-    
     config_file.write(label + '\n')
     config_file.write(s.decode('utf-8').strip("OK"))