micropython/lora: Update the implicit header option in the _SX127x.

The `_reg_update` method must be called after updating the implicit header
option's bit.

Signed-off-by: Jatty Andriean <jandriea@outlook.com>

Author: jandriea

micropython/lora/lora-sx127x/lora/sx127x.py

@@ -416,13 +416,13 @@ def configure(self, lora_cfg):
             modem_config1 |= (self._coding_rate - 4) << _MODEM_CONFIG1_CODING_RATE_SHIFT
             update_mask |= _MODEM_CONFIG1_CODING_RATE_MASK << _MODEM_CONFIG1_CODING_RATE_SHIFT
 
-        self._reg_update(_REG_MODEM_CONFIG1, update_mask, modem_config1)
-
         if "implicit_header" in lora_cfg:
             self._implicit_header = lora_cfg["implicit_header"]
             modem_config1 |= _flag(_MODEM_CONFIG1_IMPLICIT_HEADER_MODE_ON, self._implicit_header)
             update_mask |= _MODEM_CONFIG1_IMPLICIT_HEADER_MODE_ON
 
+        self._reg_update(_REG_MODEM_CONFIG1, update_mask, modem_config1)
+
         # Update MODEM_CONFIG2, for any fields that changed
         modem_config2 = 0
         update_mask = 0