diff --git a/components/soc/esp32s3/include/soc/i2c_struct.h b/components/soc/esp32s3/include/soc/i2c_struct.h
index 69c5d568d4..d68164946e 100644
--- a/components/soc/esp32s3/include/soc/i2c_struct.h
+++ b/components/soc/esp32s3/include/soc/i2c_struct.h
@@ -116,8 +116,8 @@ typedef volatile struct {
     } fifo_conf;
     union {
         struct {
-            uint8_t data;
-            uint8_t reserved[3];
+            uint32_t data                           :   8;
+            uint32_t reserved8                      :   24;
         };
         uint32_t val;
     } fifo_data;