diff --git a/flash.h b/flash.h
index de9199c..c74c96f 100644
--- a/flash.h
+++ b/flash.h
@@ -51,6 +51,12 @@
 
 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
 
+/* for pairing opcodes with their required preop */
+struct preop_opcode_pair {
+	uint8_t preop;
+	uint8_t opcode;
+};
+
 struct flashchip {
 	const char *vendor;
 	const char *name;
@@ -76,6 +82,8 @@
 	int (*write) (struct flashchip *flash, uint8_t *buf);
 	int (*read) (struct flashchip *flash, uint8_t *buf);
 
+	struct preop_opcode_pair *preop_opcode_pairs;
+
 	/* Some flash devices have an additional register space. */
 	volatile uint8_t *virtual_memory;
 	volatile uint8_t *virtual_registers;