diff --git a/adafruit_pm25/__init__.py b/adafruit_pm25/__init__.py
index 1a9ca45..82af02d 100644
--- a/adafruit_pm25/__init__.py
+++ b/adafruit_pm25/__init__.py
@@ -82,7 +82,7 @@ def read(self):
         # print([hex(i) for i in self._buffer])
 
         # check packet header
-        if (self._buffer[0] != 0x42) or (self._buffer[1] != 0x4D):
+        if not self._buffer[0:2] == b"BM":
             raise RuntimeError("Invalid PM2.5 header")
 
         # check frame length
@@ -96,7 +96,6 @@ def read(self):
             raise RuntimeError("Invalid PM2.5 checksum")
 
         # unpack data
-        frame = struct.unpack(">HHHHHHHHHHHH", self._buffer[4:28])
         (
             self.aqi_reading["pm10 standard"],
             self.aqi_reading["pm25 standard"],
@@ -110,6 +109,6 @@ def read(self):
             self.aqi_reading["particles 25um"],
             self.aqi_reading["particles 50um"],
             self.aqi_reading["particles 100um"],
-        ) = frame
+        ) = struct.unpack(">HHHHHHHHHHHH", self._buffer[4:28])
 
         return self.aqi_reading
diff --git a/adafruit_pm25/uart.py b/adafruit_pm25/uart.py
index 1b91e05..f8569ae 100644
--- a/adafruit_pm25/uart.py
+++ b/adafruit_pm25/uart.py
@@ -77,6 +77,7 @@ def _read_into_buffer(self):
         remain = self._uart.read(31)
         if not remain or len(remain) != 31:
             raise RuntimeError("Unable to read from PM2.5 (incomplete frame)")
-        for i in range(31):
-            self._buffer[i + 1] = remain[i]
-        # print([hex(i) for i in self._buffer])
+        self._buffer[1:] = remain
+
+
+#        print([hex(i) for i in self._buffer])