diff --git a/drivers/net/sfc/mcdi.c b/drivers/net/sfc/mcdi.c
index 0d4eba7..9f035b9 100644
--- a/drivers/net/sfc/mcdi.c
+++ b/drivers/net/sfc/mcdi.c
@@ -804,7 +804,7 @@
 			loff_t offset, u8 *buffer, size_t length)
 {
 	u8 inbuf[MC_CMD_NVRAM_READ_IN_LEN];
-	u8 outbuf[MC_CMD_NVRAM_READ_OUT_LEN(length)];
+	u8 outbuf[MC_CMD_NVRAM_READ_OUT_LEN(EFX_MCDI_NVRAM_LEN_MAX)];
 	size_t outlen;
 	int rc;
 
@@ -828,7 +828,7 @@
 int efx_mcdi_nvram_write(struct efx_nic *efx, unsigned int type,
 			   loff_t offset, const u8 *buffer, size_t length)
 {
-	u8 inbuf[MC_CMD_NVRAM_WRITE_IN_LEN(length)];
+	u8 inbuf[MC_CMD_NVRAM_WRITE_IN_LEN(EFX_MCDI_NVRAM_LEN_MAX)];
 	int rc;
 
 	MCDI_SET_DWORD(inbuf, NVRAM_WRITE_IN_TYPE, type);
@@ -838,7 +838,8 @@
 
 	BUILD_BUG_ON(MC_CMD_NVRAM_WRITE_OUT_LEN != 0);
 
-	rc = efx_mcdi_rpc(efx, MC_CMD_NVRAM_WRITE, inbuf, sizeof(inbuf),
+	rc = efx_mcdi_rpc(efx, MC_CMD_NVRAM_WRITE, inbuf,
+			  ALIGN(MC_CMD_NVRAM_WRITE_IN_LEN(length), 4),
 			  NULL, 0, NULL);
 	if (rc)
 		goto fail;