diff --git a/src/drivers/pc80/rtc/Kconfig b/src/drivers/pc80/rtc/Kconfig
index 0d064571e6..7a1c398d5c 100644
--- a/src/drivers/pc80/rtc/Kconfig
+++ b/src/drivers/pc80/rtc/Kconfig
@@ -9,3 +9,11 @@ config USE_PC_CMOS_ALTCENTURY
 	depends on DRIVERS_MC146818
 	help
 	  May be useful for legacy OSes that assume its presence.
+
+config PC_CMOS_BASE_PORT_BANK0
+	hex "Base port for CMOS bank 0 index/data registers"
+	default 0x70
+
+config PC_CMOS_BASE_PORT_BANK1
+	hex "Base port for CMOS bank 1 index/data registers"
+	default 0x72
diff --git a/src/drivers/pc80/rtc/mc146818rtc.c b/src/drivers/pc80/rtc/mc146818rtc.c
index f45a3a0d21..6474ecbd1a 100644
--- a/src/drivers/pc80/rtc/mc146818rtc.c
+++ b/src/drivers/pc80/rtc/mc146818rtc.c
@@ -249,11 +249,11 @@ void set_boot_successful(void)
 {
 	uint8_t index, byte;
 
-	index = inb(RTC_PORT(0)) & 0x80;
+	index = inb(RTC_PORT_BANK0(0)) & 0x80;
 	index |= RTC_BOOT_BYTE;
-	outb(index, RTC_PORT(0));
+	outb(index, RTC_PORT_BANK0(0));
 
-	byte = inb(RTC_PORT(1));
+	byte = inb(RTC_PORT_BANK0(1));
 
 	if (CONFIG(SKIP_MAX_REBOOT_CNT_CLEAR)) {
 		/*
@@ -269,5 +269,5 @@ void set_boot_successful(void)
 			byte &= 0x0f;
 	}
 
-	outb(byte, RTC_PORT(1));
+	outb(byte, RTC_PORT_BANK0(1));
 }
diff --git a/src/include/pc80/mc146818rtc.h b/src/include/pc80/mc146818rtc.h
index 383c41fc66..78184214a3 100644
--- a/src/include/pc80/mc146818rtc.h
+++ b/src/include/pc80/mc146818rtc.h
@@ -6,9 +6,10 @@
 #include <arch/io.h>
 #include <types.h>
 
-#define RTC_BASE_PORT 0x70
+#define RTC_BASE_PORT_BANK0 (CONFIG_PC_CMOS_BASE_PORT_BANK0)
+#define RTC_BASE_PORT_BANK1 (CONFIG_PC_CMOS_BASE_PORT_BANK1)
 
-#define RTC_PORT(x)	(RTC_BASE_PORT + (x))
+#define RTC_PORT_BANK0(x)	(RTC_BASE_PORT_BANK0 + (x))
 
 /* control registers - Moto names
  */
@@ -107,24 +108,24 @@
 
 static inline unsigned char cmos_read(unsigned char addr)
 {
-	int offs = 0;
+	int port = RTC_BASE_PORT_BANK0;
 	if (addr >= 128) {
-		offs = 2;
+		port = RTC_BASE_PORT_BANK1;
 		addr -= 128;
 	}
-	outb(addr, RTC_BASE_PORT + offs + 0);
-	return inb(RTC_BASE_PORT + offs + 1);
+	outb(addr, port + 0);
+	return inb(port + 1);
 }
 
 static inline void cmos_write_inner(unsigned char val, unsigned char addr)
 {
-	int offs = 0;
+	int port = RTC_BASE_PORT_BANK0;
 	if (addr >= 128) {
-		offs = 2;
+		port = RTC_BASE_PORT_BANK1;
 		addr -= 128;
 	}
-	outb(addr, RTC_BASE_PORT + offs + 0);
-	outb(val, RTC_BASE_PORT + offs + 1);
+	outb(addr, port + 0);
+	outb(val, port + 1);
 }
 
 static inline u8 cmos_disable_rtc(void)