diff --git a/include/libopencm3/stm32/f4/memorymap.h b/include/libopencm3/stm32/f4/memorymap.h
index 76d827fa..c3a820ed 100644
--- a/include/libopencm3/stm32/f4/memorymap.h
+++ b/include/libopencm3/stm32/f4/memorymap.h
@@ -48,10 +48,10 @@
 #define RTC_BASE			(PERIPH_BASE_APB1 + 0x2800)
 #define WWDG_BASE			(PERIPH_BASE_APB1 + 0x2c00)
 #define IWDG_BASE			(PERIPH_BASE_APB1 + 0x3000)
-#define I2S3_EXT_BASE			(PERIPH_BASE_APB1 + 0x3400)
+#define I2S2_EXT_BASE			(PERIPH_BASE_APB1 + 0x3400)
 #define SPI2_BASE			(PERIPH_BASE_APB1 + 0x3800)
 #define SPI3_BASE			(PERIPH_BASE_APB1 + 0x3c00)
-#define I2S2_EXT_BASE			(PERIPH_BASE_APB1 + 0x4000)
+#define I2S3_EXT_BASE			(PERIPH_BASE_APB1 + 0x4000)
 #define USART2_BASE			(PERIPH_BASE_APB1 + 0x4400)
 #define USART3_BASE			(PERIPH_BASE_APB1 + 0x4800)
 #define UART4_BASE			(PERIPH_BASE_APB1 + 0x4c00)