diff --git a/sw/airborne/peripherals/mpu9250_i2c.c b/sw/airborne/peripherals/mpu9250_i2c.c
index 3237c35224..25ae8e298b 100644
--- a/sw/airborne/peripherals/mpu9250_i2c.c
+++ b/sw/airborne/peripherals/mpu9250_i2c.c
@@ -114,8 +114,15 @@ void mpu9250_i2c_event(struct Mpu9250_I2c *mpu)
         mpu->data_rates.rates.r = Int16FromBuf(mpu->i2c_trans.buf, 13);
 
         // if we are reading slaves through the mpu, copy the ext_sens_data
-        if ((mpu->config.i2c_bypass == FALSE) && (mpu->config.nb_slaves > 0))
-          memcpy(mpu->data_ext, (void *) &(mpu->i2c_trans.buf[15]), mpu->config.nb_bytes - 15);
+        if ((mpu->config.i2c_bypass == FALSE) && (mpu->config.nb_slaves > 0)) {
+          /* the buffer is volatile, since filled from ISR
+           * but we know it's ok to use it here so we silence the warning
+           */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wcast-qual"
+          memcpy(mpu->data_ext, (uint8_t *) &(mpu->i2c_trans.buf[15]), mpu->config.nb_bytes - 15);
+#pragma GCC diagnostic pop
+        }
 
         mpu->data_available = TRUE;
       }
diff --git a/sw/airborne/peripherals/mpu9250_spi.c b/sw/airborne/peripherals/mpu9250_spi.c
index 0fff4d5330..82f03067e1 100644
--- a/sw/airborne/peripherals/mpu9250_spi.c
+++ b/sw/airborne/peripherals/mpu9250_spi.c
@@ -114,8 +114,15 @@ void mpu9250_spi_event(struct Mpu9250_Spi *mpu)
         mpu->data_rates.rates.r = Int16FromBuf(mpu->rx_buf, 14);
 
         // if we are reading slaves, copy the ext_sens_data
-        if (mpu->config.nb_slaves > 0)
-          memcpy(mpu->data_ext, (void *) &(mpu->rx_buf[16]), mpu->config.nb_bytes - 15);
+        if (mpu->config.nb_slaves > 0) {
+          /* the buffer is volatile, since filled from ISR
+           * but we know it's ok to use it here so we silence the warning
+           */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wcast-qual"
+          memcpy(mpu->data_ext, (uint8_t *) &(mpu->rx_buf[16]), mpu->config.nb_bytes - 15);
+#pragma GCC diagnostic pop
+        }
 
         mpu->data_available = TRUE;
       }