diff --git a/api_examples/demo.c b/api_examples/demo.c
index 2510ed8..df9c4bd 100644
--- a/api_examples/demo.c
+++ b/api_examples/demo.c
@@ -43,12 +43,11 @@ static char buf[BUF_SZ];
 
 int main(int argc, char *argv[])
 {
-	int rv = 0;
-	int h, i, j;
-	int devs_no;
+	int rv = 0, h, i, j, devs_no;
 	struct api_signature *sig = NULL;
 	ulong start, now;
 	struct device_info *di;
+	lbasize_t rlen;
 
 	if (!api_search_sig(&sig))
 		return -1;
@@ -96,7 +95,6 @@ int main(int argc, char *argv[])
 	if (devs_no == 0)
 		return -1;
 
-
 	printf("\n*** Show devices ***\n");
 	for (i = 0; i < devs_no; i++) {
 		test_dump_di(i);
@@ -133,7 +131,7 @@ int main(int argc, char *argv[])
 		if ((rv = ub_dev_open(i)) != 0)
 			errf("open device %d error %d\n", i, rv);
 
-		else if ((rv = ub_dev_read(i, buf, 1, 0)) != 0)
+		else if ((rv = ub_dev_read(i, buf, 1, 0, &rlen)) != 0)
 			errf("could not read from device %d, error %d\n", i, rv);
 		else {
 			printf("Sector 0 dump (512B):\n");
diff --git a/api_examples/glue.c b/api_examples/glue.c
index 200b163..eff6a7e 100644
--- a/api_examples/glue.c
+++ b/api_examples/glue.c
@@ -1,7 +1,5 @@
 /*
- * (C) Copyright 2007 Semihalf
- *
- * Written by: Rafal Jaworowski <raj@semihalf.com>
+ * (C) Copyright 2007-2008 Semihalf, Rafal Jaworowski <raj@semihalf.com>
  *
  * See file CREDITS for list of people who contributed to this
  * project.
@@ -57,8 +55,8 @@ static int valid_sig(struct api_signature *sig)
  *
  * returns 1/0 depending on found/not found result
  */
-int api_search_sig(struct api_signature **sig) {
-
+int api_search_sig(struct api_signature **sig)
+{
 	unsigned char *sp;
 	uint32_t search_start = 0;
 	uint32_t search_end = 0;
@@ -133,8 +131,7 @@ void ub_reset(void)
 	syscall(API_RESET, NULL);
 }
 
-#define MR_MAX 5
-static struct mem_region mr[MR_MAX];
+static struct mem_region mr[UB_MAX_MR];
 static struct sys_info si;
 
 struct sys_info * ub_get_sys_info(void)
@@ -143,7 +140,7 @@ struct sys_info * ub_get_sys_info(void)
 
 	memset(&si, 0, sizeof(struct sys_info));
 	si.mr = mr;
-	si.mr_no = MR_MAX;
+	si.mr_no = UB_MAX_MR;
 	memset(&mr, 0, sizeof(mr));
 
 	if (!syscall(API_GET_SYS_INFO, &err, (u_int32_t)&si))
@@ -178,17 +175,15 @@ unsigned long ub_get_timer(unsigned long base)
  *
  * devices
  *
- * Devices are identified by handles: numbers 0, 1, 2, ..., MAX_DEVS-1
+ * Devices are identified by handles: numbers 0, 1, 2, ..., UB_MAX_DEV-1
  *
  ***************************************************************************/
 
-#define MAX_DEVS 6
-
-static struct device_info devices[MAX_DEVS];
+static struct device_info devices[UB_MAX_DEV];
 
 struct device_info * ub_dev_get(int i)
 {
-	return ((i < 0 || i >= MAX_DEVS) ? NULL : &devices[i]);
+	return ((i < 0 || i >= UB_MAX_DEV) ? NULL : &devices[i]);
 }
 
 /*
@@ -202,7 +197,7 @@ int ub_dev_enum(void)
 	struct device_info *di;
 	int n = 0;
 
-	memset(&devices, 0, sizeof(struct device_info) * MAX_DEVS);
+	memset(&devices, 0, sizeof(struct device_info) * UB_MAX_DEV);
 	di = &devices[0];
 
 	if (!syscall(API_DEV_ENUM, NULL, di))
@@ -210,7 +205,7 @@ int ub_dev_enum(void)
 
 	while (di->cookie != NULL) {
 
-		if (++n >= MAX_DEVS)
+		if (++n >= UB_MAX_DEV)
 			break;
 
 		/* take another device_info */
@@ -236,7 +231,7 @@ int ub_dev_open(int handle)
 	struct device_info *di;
 	int err = 0;
 
-	if (handle < 0 || handle >= MAX_DEVS)
+	if (handle < 0 || handle >= UB_MAX_DEV)
 		return API_EINVAL;
 
 	di = &devices[handle];
@@ -251,7 +246,7 @@ int ub_dev_close(int handle)
 {
 	struct device_info *di;
 
-	if (handle < 0 || handle >= MAX_DEVS)
+	if (handle < 0 || handle >= UB_MAX_DEV)
 		return API_EINVAL;
 
 	di = &devices[handle];
@@ -272,7 +267,7 @@ int ub_dev_close(int handle)
  */
 static int dev_valid(int handle)
 {
-	if (handle < 0 || handle >= MAX_DEVS)
+	if (handle < 0 || handle >= UB_MAX_DEV)
 		return 0;
 
 	if (devices[handle].state != DEV_STA_OPEN)
@@ -292,7 +287,8 @@ static int dev_stor_valid(int handle)
 	return 1;
 }
 
-int ub_dev_read(int handle, void *buf, lbasize_t len, lbastart_t start)
+int ub_dev_read(int handle, void *buf, lbasize_t len, lbastart_t start,
+		lbasize_t *rlen)
 {
 	struct device_info *di;
 	lbasize_t act_len;
@@ -303,15 +299,12 @@ int ub_dev_read(int handle, void *buf, lbasize_t len, lbastart_t start)
 
 	di = &devices[handle];
 	if (!syscall(API_DEV_READ, &err, di, buf, &len, &start, &act_len))
-		return -1;
-
-	if (err)
-		return err;
+		return API_ESYSC;
 
-	if (act_len != len)
-		return API_EIO;
+	if (!err && rlen)
+		*rlen = act_len;
 
-	return 0;
+	return err;
 }
 
 static int dev_net_valid(int handle)
@@ -325,7 +318,7 @@ static int dev_net_valid(int handle)
 	return 1;
 }
 
-int ub_dev_recv(int handle, void *buf, int len)
+int ub_dev_recv(int handle, void *buf, int len, int *rlen)
 {
 	struct device_info *di;
 	int err = 0, act_len;
@@ -335,12 +328,12 @@ int ub_dev_recv(int handle, void *buf, int len)
 
 	di = &devices[handle];
 	if (!syscall(API_DEV_READ, &err, di, buf, &len, &act_len))
-		return -1;
+		return API_ESYSC;
 
-	if (err)
-		return -1;
+	if (!err && rlen)
+		*rlen = act_len;
 
-	return act_len;
+	 return (err);
 }
 
 int ub_dev_send(int handle, void *buf, int len)
@@ -353,7 +346,7 @@ int ub_dev_send(int handle, void *buf, int len)
 
 	di = &devices[handle];
 	if (!syscall(API_DEV_WRITE, &err, di, buf, &len))
-		return -1;
+		return API_ESYSC;
 
 	return err;
 }
@@ -379,7 +372,6 @@ void ub_env_set(const char *name, char *value)
 	syscall(API_ENV_SET, NULL, (uint32_t)name, (uint32_t)value);
 }
 
-
 static char env_name[256];
 
 const char * ub_env_enum(const char *last)
diff --git a/api_examples/glue.h b/api_examples/glue.h
index 0adb8b3..6bf47d0 100644
--- a/api_examples/glue.h
+++ b/api_examples/glue.h
@@ -32,6 +32,9 @@
 
 #define API_SEARCH_LEN		(3 * 1024 * 1024)	/* 3MB search range */
 
+#define UB_MAX_MR	5	/* max mem regions number */
+#define UB_MAX_DEV	6	/* max devices number */
+
 extern void *syscall_ptr;
 extern uint32_t search_hint;
 
@@ -39,9 +42,10 @@ int	syscall(int, int *, ...);
 int	api_search_sig(struct api_signature **sig);
 
 /*
- * ub_ library calls are part of the application, not U-Boot code!  They are
- * front-end wrappers that are used by the consumer application: they prepare
- * arguments for particular syscall and jump to the low level syscall()
+ * The ub_ library calls are part of the application, not U-Boot code!  They
+ * are front-end wrappers that are used by the consumer application: they
+ * prepare arguments for particular syscall and jump to the low level
+ * syscall()
  */
 
 /* console */
@@ -67,10 +71,10 @@ const char *	ub_env_enum(const char *last);
 int			ub_dev_enum(void);
 int			ub_dev_open(int handle);
 int			ub_dev_close(int handle);
-int			ub_dev_read(int handle, void *buf,
-				lbasize_t len, lbastart_t start);
+int			ub_dev_read(int handle, void *buf, lbasize_t len,
+				lbastart_t start, lbasize_t *rlen);
 int			ub_dev_send(int handle, void *buf, int len);
-int			ub_dev_recv(int handle, void *buf, int len);
+int			ub_dev_recv(int handle, void *buf, int len, int *rlen);
 struct device_info *	ub_dev_get(int);
 
 #endif /* _API_GLUE_H_ */
diff --git a/include/api_public.h b/include/api_public.h
index d3164f6..5940d81 100644
--- a/include/api_public.h
+++ b/include/api_public.h
@@ -57,6 +57,7 @@
 #define API_ENOMEM		3	/* no memory		*/
 #define API_EBUSY		4	/* busy, occupied etc.	*/
 #define API_EIO			5	/* I/O error		*/
+#define API_ESYSC		6	/* syscall error	*/
 
 typedef	int (*scp_t)(int, int *, ...);