diff --git a/src/drivers/intel/cavs/dmic.c b/src/drivers/intel/cavs/dmic.c
index 05074921806d..7b2352126012 100644
--- a/src/drivers/intel/cavs/dmic.c
+++ b/src/drivers/intel/cavs/dmic.c
@@ -1147,9 +1147,7 @@ static int dmic_set_config(struct dai *dai, struct sof_ipc_dai_config *config)
 	 * "prm" is initialized with default params for all HW controllers
 	 */
 	if (!dmic_prm[0]) {
-		size = sizeof(struct sof_ipc_dai_dmic_params)
-			+ DMIC_HW_CONTROLLERS
-			* sizeof(struct sof_ipc_dai_dmic_pdm_ctrl);
+		size = sizeof(struct sof_ipc_dai_dmic_params);
 		dmic_prm[0] = rzalloc(SOF_MEM_ZONE_SYS_RUNTIME, 0,
 				      SOF_MEM_CAPS_RAM,
 				      DMIC_HW_FIFOS * size);
@@ -1162,11 +1160,11 @@ static int dmic_set_config(struct dai *dai, struct sof_ipc_dai_config *config)
 				((uint8_t *)dmic_prm[i - 1] + size);
 	}
 
-	/* Copy the new DMIC params to persistent.  The last request
-	 * determines the parameters.
+	/* Copy the new DMIC params header (all but not pdm[]) to persistent.
+	 * The last arrived request determines the parameters.
 	 */
 	ret = memcpy_s(dmic_prm[di], sizeof(*dmic_prm[di]), &config->dmic,
-		       sizeof(struct sof_ipc_dai_dmic_params));
+		       offsetof(struct sof_ipc_dai_dmic_params, pdm));
 	assert(!ret);
 
 	/* copy the pdm controller params from ipc */
diff --git a/src/include/ipc/dai-intel.h b/src/include/ipc/dai-intel.h
index e57afd09d1c6..a9628b820071 100644
--- a/src/include/ipc/dai-intel.h
+++ b/src/include/ipc/dai-intel.h
@@ -57,6 +57,9 @@
 /* bclk idle */
 #define SOF_DAI_INTEL_SSP_CLKCTRL_BCLK_IDLE_HIGH	BIT(5)
 
+/* DMIC max. four controllers for eight microphone channels */
+#define SOF_DAI_INTEL_DMIC_NUM_CTRL			4
+
 /* SSP Configuration Request - SOF_IPC_DAI_SSP_CONFIG */
 struct sof_ipc_dai_ssp_params {
 	uint32_t reserved0;
@@ -143,7 +146,7 @@ struct sof_ipc_dai_dmic_pdm_ctrl {
  * version number used in configuration data is checked vs. version used by
  * device driver src/drivers/dmic.c need to match. It is incremented from
  * initial value 1 if updates done for the to driver would alter the operation
- * of the microhone.
+ * of the microphone.
  *
  * Note: The microphone clock (pdmclk_min, pdmclk_max, duty_min, duty_max)
  * parameters need to be set as defined in microphone data sheet. E.g. clock
@@ -168,6 +171,7 @@ struct sof_ipc_dai_dmic_pdm_ctrl {
  * met. The unit for both is microseconds (us). Exceed of 100 ms will be
  * treated as an error.
  */
+
 struct sof_ipc_dai_dmic_params {
 	uint32_t reserved0;
 	uint32_t driver_ipc_version;	/**< Version (1..N) */
@@ -178,12 +182,13 @@ struct sof_ipc_dai_dmic_params {
 	uint32_t fifo_fs;	/**< FIFO sample rate in Hz (8000..96000) */
 	uint32_t reserved_1;	/**< Reserved */
 	uint16_t fifo_bits;	/**< FIFO word length (16 or 32) */
-	uint16_t reserved_2;	/**< Reserved */
+	uint16_t fifo_bits_b;	/**< Deprecated since firmware ABI 3.0.1 */
 
 	uint16_t duty_min;	/**< Min. mic clock duty cycle in % (20..80) */
 	uint16_t duty_max;	/**< Max. mic clock duty cycle in % (min..80) */
 
-	uint32_t num_pdm_active; /**< Number of active pdm controllers */
+	uint32_t num_pdm_active; /**< Number of active pdm controllers. */
+				 /**< Range is 1..SOF_DAI_INTEL_DMIC_NUM_CTRL */
 
 	uint32_t wake_up_time;      /**< Time from clock start to data (us) */
 	uint32_t min_clock_on_time; /**< Min. time that clk is kept on (us) */
@@ -192,8 +197,8 @@ struct sof_ipc_dai_dmic_params {
 	/* reserved for future use */
 	uint32_t reserved[5];
 
-	/**< variable number of pdm controller config */
-	struct sof_ipc_dai_dmic_pdm_ctrl pdm[0];
+	/**< PDM controllers configuration */
+	struct sof_ipc_dai_dmic_pdm_ctrl pdm[SOF_DAI_INTEL_DMIC_NUM_CTRL];
 } __attribute__((packed));
 
 #endif /* __IPC_DAI_INTEL_H__ */