diff --git a/plat/intel/soc/common/sip/socfpga_sip_fcs.c b/plat/intel/soc/common/sip/socfpga_sip_fcs.c
index 3b0b370..0166eb7 100644
--- a/plat/intel/soc/common/sip/socfpga_sip_fcs.c
+++ b/plat/intel/soc/common/sip/socfpga_sip_fcs.c
@@ -1269,7 +1269,7 @@
 		memcpy((uint8_t *) &payload[i], (uint8_t *) mac_offset,
 		src_size - data_size);
 
-		memset((void *)&dst_addr, 0, sizeof(dst_size));
+		memset((void *) dst_addr, 0, *dst_size);
 
 		i += (src_size - data_size) / MBOX_WORD_BYTE;
 	}
@@ -1874,7 +1874,7 @@
 		memcpy((uint8_t *) &payload[i], (uint8_t *) sig_pubkey_offset,
 			src_size - data_size);
 
-		memset((void *)&dst_addr, 0, sizeof(dst_size));
+		memset((void *) dst_addr, 0, *dst_size);
 
 		i += (src_size - data_size) / MBOX_WORD_BYTE;
 	}