diff --git a/sys/dev/isp/isp.c b/sys/dev/isp/isp.c
index 5d1c824deff..c3470529657 100644
--- a/sys/dev/isp/isp.c
+++ b/sys/dev/isp/isp.c
@@ -4333,12 +4333,7 @@ isp_read_nvram_2400(ispsoftc_t *isp)
 	uint32_t addr, csum, lwrds, *dptr;
 	uint8_t nvram_data[ISP2400_NVRAM_SIZE];
 
-	if (isp->isp_port) {
-		addr = ISP2400_NVRAM_PORT1_ADDR;
-	} else {
-		addr = ISP2400_NVRAM_PORT0_ADDR;
-	}
-
+	addr = ISP2400_NVRAM_PORT_ADDR(isp->isp_port);
 	dptr = (uint32_t *) nvram_data;
 	for (lwrds = 0; lwrds < ISP2400_NVRAM_SIZE >> 2; lwrds++) {
 		isp_rd_2400_nvram(isp, addr++, dptr++);
diff --git a/sys/dev/isp/ispreg.h b/sys/dev/isp/ispreg.h
index 5d04ad2b440..98b9a6c0bf0 100644
--- a/sys/dev/isp/ispreg.h
+++ b/sys/dev/isp/ispreg.h
@@ -213,8 +213,7 @@ typedef struct {
 /*
  * Qlogic 2400 NVRAM is an array of 512 bytes with a 32 bit checksum.
  */
-#define	ISP2400_NVRAM_PORT0_ADDR	0x80
-#define	ISP2400_NVRAM_PORT1_ADDR	0x180
+#define	ISP2400_NVRAM_PORT_ADDR(c)	(0x100 * (c) + 0x80)
 #define	ISP2400_NVRAM_SIZE		512
 
 #define	ISP2400_NVRAM_VERSION(c)		((c)[4] | ((c)[5] << 8))