diff --git a/pmme-device/c-version/main/pmme.c b/pmme-device/c-version/main/pmme.c
index 7acdc68..5b2443a 100644
--- a/pmme-device/c-version/main/pmme.c
+++ b/pmme-device/c-version/main/pmme.c
@@ -78,7 +78,7 @@ void send_pms7003_command(uint8_t cmd, uint8_t datah, uint8_t datal) {
 
 void read_pm_data(uint8_t *buf) {
     uint16_t checksum = 0;
-    for (int i = 0; i <= 29; i++) {
+    for (int i = 0; i <= 28; i++) {
         checksum += buf[i];
     }
     uint16_t c = (((uint16_t)buf[30]) << 8) | ((uint16_t)buf[31]);
@@ -130,13 +130,12 @@ void pm_sensor_task(void *pvParameters) {
         int len = uart_read_bytes(UART_NUM, uart_data, BUF_SIZE, 100 / portTICK_PERIOD_MS);
         // ESP_LOGI(TAG, "Received %d bytes from sensor", len);
         if (len > 0) {
-            if (len == 32 && (uart_data[0] != 0x42 || uart_data[1] != 0x4D)) {
+            if (uart_data[0] != 0x42 || uart_data[1] != 0x4D) {
                 ESP_LOGW(TAG, "Frame Start does not match 0x42, 0x4D, instead got %x %x", uart_data[0], uart_data[1]);
-            } else {
+            } else if (len == 32) {
                 read_pm_data(uart_data);
-                // for(int i = 0; i < len && i < BUF_SIZE; i++) {
-                //     ESP_LOGI(TAG, "0x%02X", uart_data[i]);
-                // }
+            } else {
+                ESP_LOGW(TAG, "Unexpected frame length: %d", len);
             }
         }
         uart_flush(UART_NUM);