diff --git a/rtl837x_flash.c b/rtl837x_flash.c
index 3f429b3..59d9de6 100644
--- a/rtl837x_flash.c
+++ b/rtl837x_flash.c
@@ -7,7 +7,7 @@
 #include "rtl837x_stdio.h"
 #include "rtl837x_sfr.h"
 
-__xdata unsigned char dio_enabled;
+__xdata uint8_t dio_enabled;
 
 
 /*
@@ -36,7 +36,7 @@ void flash_configure_mmio(void)
  * This configures uses fast single IO at 20.8 MHz when the CPU clock is at 20.8MHz
  * and 62.5MHz when the CPU clock is configured at 125MHz
  */
-void flash_init(unsigned char enable_dio)
+void flash_init(uint8_t enable_dio)
 {
 	if (enable_dio) {
 		// Configure fast DIO via divider/DIO/SIOconfig = 4 and read-cmd being 0xbb (for mmio)
@@ -271,7 +271,7 @@ void flash_block_erase(uint32_t addr)
 
 void flash_write_bytes(uint32_t addr, __xdata uint8_t *ptr, uint8_t len)
 {
-	unsigned char exit_loop = 0;
+	uint8_t exit_loop = 0;
 
 	while(1) {
 		flash_write_enable();
diff --git a/rtl837x_flash.h b/rtl837x_flash.h
index 8e20c22..1b4d867 100644
--- a/rtl837x_flash.h
+++ b/rtl837x_flash.h
@@ -3,7 +3,7 @@
 
 #include <stdint.h>
 uint8_t flash_read_status(void);
-void flash_init(unsigned char enable_dio);
+void flash_init(uint8_t enable_dio);
 void flash_read_uid(void);
 void flash_write_enable(void);
 void flash_dump(uint32_t addr, uint8_t len);
diff --git a/rtl837x_regs.h b/rtl837x_regs.h
index 8d98a58..8f66391 100644
--- a/rtl837x_regs.h
+++ b/rtl837x_regs.h
@@ -20,10 +20,11 @@
 /*
  * 5 Bits each give the state of the 2 SerDes of the RTL8372
  * Values are:
- * 0x1A: 10GBit USXGMII?
- * 0x5: 2.5GBit: HISGMII ???
- * 0x4: 1GBit: SGMII
  */
+#define SDS_SGMII		0x02
+#define SDS_1000BX_FIBER	0x04
+#define SDS_HISGMII		0x12
+#define SDS_10GR		0x1a
 
 #define RTL837X_REG_LINKS 0x63f0
 /* Each nibble encodes the link state of a port.
diff --git a/rtl837x_stdio.h b/rtl837x_stdio.h
index 0f25c77..708dcd4 100644
--- a/rtl837x_stdio.h
+++ b/rtl837x_stdio.h
@@ -2,7 +2,7 @@
 #define _RTL837X_STDIO_H_
 
 void print_string(__code char *p);
-void print_short(unsigned short a);
-void print_byte(unsigned char a);
+void print_short(uint16_t a);
+void print_byte(uint8_t a);
 
 #endif