diff --git a/drivers/spi/mtk_snfi_spi.c b/drivers/spi/mtk_snfi_spi.c
index b6ab5fa3ada..65d0ce0981b 100644
--- a/drivers/spi/mtk_snfi_spi.c
+++ b/drivers/spi/mtk_snfi_spi.c
@@ -64,8 +64,7 @@ static int mtk_snfi_adjust_op_size(struct spi_slave *slave,
 	 * or the output+input data must not exceed the GPRAM size.
 	 */
 
-	nbytes = sizeof(op->cmd.opcode) + op->addr.nbytes +
-		op->dummy.nbytes;
+	nbytes = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
 
 	if (nbytes + op->data.nbytes <= SNFI_GPRAM_SIZE)
 		return 0;
diff --git a/drivers/spi/spi-mem-nodm.c b/drivers/spi/spi-mem-nodm.c
index 765f05fe542..db54101383c 100644
--- a/drivers/spi/spi-mem-nodm.c
+++ b/drivers/spi/spi-mem-nodm.c
@@ -27,7 +27,7 @@ int spi_mem_exec_op(struct spi_slave *slave,
 			tx_buf = op->data.buf.out;
 	}
 
-	op_len = sizeof(op->cmd.opcode) + op->addr.nbytes + op->dummy.nbytes;
+	op_len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
 	op_buf = calloc(1, op_len);
 
 	ret = spi_claim_bus(slave);
@@ -89,7 +89,7 @@ int spi_mem_adjust_op_size(struct spi_slave *slave,
 {
 	unsigned int len;
 
-	len = sizeof(op->cmd.opcode) + op->addr.nbytes + op->dummy.nbytes;
+	len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
 	if (slave->max_write_size && len > slave->max_write_size)
 		return -EINVAL;
 
diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
index 427f7c13c56..541cd0e5a77 100644
--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c
@@ -167,6 +167,9 @@ bool spi_mem_default_supports_op(struct spi_slave *slave,
 	if (op->cmd.dtr || op->addr.dtr || op->dummy.dtr || op->data.dtr)
 		return false;
 
+	if (op->cmd.nbytes != 1)
+		return false;
+
 	return true;
 }
 EXPORT_SYMBOL_GPL(spi_mem_default_supports_op);
@@ -273,8 +276,7 @@ int spi_mem_exec_op(struct spi_slave *slave, const struct spi_mem_op *op)
 	}
 
 #ifndef __UBOOT__
-	tmpbufsize = sizeof(op->cmd.opcode) + op->addr.nbytes +
-		     op->dummy.nbytes;
+	tmpbufsize = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
 
 	/*
 	 * Allocate a buffer to transmit the CMD, ADDR cycles with kmalloc() so
@@ -289,7 +291,7 @@ int spi_mem_exec_op(struct spi_slave *slave, const struct spi_mem_op *op)
 
 	tmpbuf[0] = op->cmd.opcode;
 	xfers[xferpos].tx_buf = tmpbuf;
-	xfers[xferpos].len = sizeof(op->cmd.opcode);
+	xfers[xferpos].len = op->cmd.nbytes;
 	xfers[xferpos].tx_nbits = op->cmd.buswidth;
 	spi_message_add_tail(&xfers[xferpos], &msg);
 	xferpos++;
@@ -353,7 +355,7 @@ int spi_mem_exec_op(struct spi_slave *slave, const struct spi_mem_op *op)
 			tx_buf = op->data.buf.out;
 	}
 
-	op_len = sizeof(op->cmd.opcode) + op->addr.nbytes + op->dummy.nbytes;
+	op_len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
 
 	/*
 	 * Avoid using malloc() here so that we can use this code in SPL where
@@ -442,8 +444,7 @@ int spi_mem_adjust_op_size(struct spi_slave *slave, struct spi_mem_op *op)
 	if (!ops->mem_ops || !ops->mem_ops->exec_op) {
 		unsigned int len;
 
-		len = sizeof(op->cmd.opcode) + op->addr.nbytes +
-			op->dummy.nbytes;
+		len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
 		if (slave->max_write_size && len > slave->max_write_size)
 			return -EINVAL;
 
diff --git a/include/spi-mem.h b/include/spi-mem.h
index 8bd44596747..fe249f77ba1 100644
--- a/include/spi-mem.h
+++ b/include/spi-mem.h
@@ -17,6 +17,7 @@ struct udevice;
 	{							\
 		.buswidth = __buswidth,				\
 		.opcode = __opcode,				\
+		.nbytes = 1,					\
 	}
 
 #define SPI_MEM_OP_ADDR(__nbytes, __val, __buswidth)		\
@@ -69,6 +70,8 @@ enum spi_mem_data_dir {
 
 /**
  * struct spi_mem_op - describes a SPI memory operation
+ * @cmd.nbytes: number of opcode bytes (only 1 or 2 are valid). The opcode is
+ *		sent MSB-first.
  * @cmd.buswidth: number of IO lines used to transmit the command
  * @cmd.opcode: operation opcode
  * @cmd.dtr: whether the command opcode should be sent in DTR mode or not
@@ -92,9 +95,10 @@ enum spi_mem_data_dir {
  */
 struct spi_mem_op {
 	struct {
+		u8 nbytes;
 		u8 buswidth;
-		u8 opcode;
 		u8 dtr : 1;
+		u16 opcode;
 	} cmd;
 
 	struct {