diff --git a/core/esp_spi.c b/core/esp_spi.c
index c6c0546..7a8704c 100644
--- a/core/esp_spi.c
+++ b/core/esp_spi.c
@@ -178,7 +178,7 @@ static void _spi_buf_prepare(uint8_t bus, size_t len, spi_endianness_t e, spi_wo
     if (e == SPI_LITTLE_ENDIAN || word_size == SPI_32BIT) return;
 
     size_t count = word_size == SPI_16BIT ? (len + 1) / 2 : (len + 3) / 4;
-    uint32_t *data = (uint32_t *)&SPI(bus).W0;
+    uint32_t *data = (uint32_t *)SPI(bus).W;
     for (size_t i = 0; i < count; i ++)
     {
         data[i] = word_size == SPI_16BIT
@@ -193,14 +193,14 @@ static void _spi_buf_transfer(uint8_t bus, const void *out_data, void *in_data,
     _wait(bus);
     size_t bytes = len * (uint8_t)word_size;
     _set_size(bus, bytes);
-    memcpy((void *)&SPI(bus).W0, out_data, bytes);
+    memcpy((void *)SPI(bus).W, out_data, bytes);
     _spi_buf_prepare(bus, len, e, word_size);
     _start(bus);
     _wait(bus);
     if (in_data)
     {
         _spi_buf_prepare(bus, len, e, word_size);
-        memcpy(in_data, (void *)&SPI(bus).W0, bytes);
+        memcpy(in_data, (void *)SPI(bus).W, bytes);
     }
 }
 
diff --git a/include/espressif/spi_flash.h b/include/espressif/spi_flash.h
index f08cda9..61f8ae9 100644
--- a/include/espressif/spi_flash.h
+++ b/include/espressif/spi_flash.h
@@ -36,7 +36,7 @@ sdk_SpiFlashOpResult sdk_spi_flash_erase_sector(uint16_t sec);
    src is pointer to a buffer to read bytes from. Should be 4-byte aligned.
    size is length of buffer in bytes. Should be a multiple of 4.
 */
-sdk_SpiFlashOpResult sdk_spi_flash_write(uint32_t des_addr, const void *src, uint32_t size);
+sdk_SpiFlashOpResult sdk_spi_flash_write(uint32_t des_addr, uint32_t *src, uint32_t size);
 
 /* Read data from flash.
 
@@ -44,8 +44,12 @@ sdk_SpiFlashOpResult sdk_spi_flash_write(uint32_t des_addr, const void *src, uin
    des is pointer to a buffer to read bytes into. Should be 4-byte aligned.
    size is number of bytes to read. Should be a multiple of 4.
 */
-sdk_SpiFlashOpResult sdk_spi_flash_read(uint32_t src_addr, void *des, uint32_t size);
+sdk_SpiFlashOpResult sdk_spi_flash_read(uint32_t src_addr, uint32_t *des, uint32_t size);
 
+/* SDK uses this structure internally to account for flash size.
+
+   See flashchip.h for more info.
+*/
 extern sdk_flashchip_t sdk_flashchip;
 
 #ifdef	__cplusplus
diff --git a/open_esplibs/libmain/timers.c b/open_esplibs/libmain/timers.c
index 1359fc1..1e2a920 100644
--- a/open_esplibs/libmain/timers.c
+++ b/open_esplibs/libmain/timers.c
@@ -1,4 +1,5 @@
 #include "etstimer.h"
+#include "stdio.h"
 
 struct timer_list_st {
     struct timer_list_st *next;