diff --git a/src/arch/i386/image/nbi.c b/src/arch/i386/image/nbi.c
index 7a2db255..b7c13e59 100644
--- a/src/arch/i386/image/nbi.c
+++ b/src/arch/i386/image/nbi.c
@@ -95,7 +95,7 @@ static struct ebinfo loaderinfo = {
  * @v context		NBI image context
  * @ret	True		Image is a valid NBI image
  * @ret	False		Image is not a valid NBI image
- * @err	EBADIMG		Image is not a valid NBI image
+ * @err	ENOEXEC		Image is not a valid NBI image
  * 
  * "context" is filled in with a context pointer suitable for passing to
  * nbi_load() and nbi_boot().
@@ -106,14 +106,14 @@ static int nbi_probe ( physaddr_t start, off_t len, void **context ) {
 
 	if ( (unsigned)len < sizeof ( imgheader ) ) {
 		DBG ( "NBI image too small\n" );
-		errno = EBADIMG;
+		errno = ENOEXEC;
 		return 0;
 	}
 
 	copy_from_phys ( &imgheader, start, sizeof ( imgheader ) );
 
 	if ( imgheader.magic != NBI_MAGIC ) {
-		errno = EBADIMG;
+		errno = ENOEXEC;
 		return 0;
 	}
 
@@ -168,7 +168,7 @@ static int nbi_load_segment ( physaddr_t dest, off_t imglen,
  * @v process		Function to call for each segment
  * @ret True		All segments were processed successfully
  * @ret False		An error occurred processing a segment
- * @err EBADIMG		Image is not a valid NBI image
+ * @err ENOEXEC		Image is not a valid NBI image
  * @err other		As returned by the "process" function
  *
  */
@@ -200,7 +200,7 @@ static int nbi_process_segments ( physaddr_t start, off_t len,
 		if ( sh.length == 0 ) {
 			/* Avoid infinite loop? */
 			DBG ( "NBI invalid segheader length 0\n" );
-			errno = EBADIMG;
+			errno = ENOEXEC;
 			return 0;
 		}
 		
@@ -240,7 +240,7 @@ static int nbi_process_segments ( physaddr_t start, off_t len,
 		sh_off += NBI_LENGTH ( sh.length );
 		if ( sh_off >= NBI_HEADER_LENGTH ) {
 			DBG ( "NBI header overflow\n" );
-			errno = EBADIMG;
+			errno = ENOEXEC;
 			return 0;
 		}
 
@@ -249,7 +249,7 @@ static int nbi_process_segments ( physaddr_t start, off_t len,
 	if ( offset != len ) {
 		DBG ( "NBI length mismatch (file %d, metadata %d)\n",
 		      len, offset );
-		errno = EBADIMG;
+		errno = ENOEXEC;
 		return 0;
 	}
 
@@ -264,7 +264,7 @@ static int nbi_process_segments ( physaddr_t start, off_t len,
  * @v context		NBI context (as returned by nbi_probe())
  * @ret True		Image loaded into memory
  * @ret False		Image not loaded into memory
- * @err EBADIMG		Image is not a valid NBI image
+ * @err ENOEXEC		Image is not a valid NBI image
  * @err other		As returned by nbi_process_segments()
  * @err other		As returned by nbi_prepare_segment()
  * @err other		As returned by nbi_load_segment()
@@ -275,7 +275,7 @@ static int nbi_load ( physaddr_t start, off_t len, void *context ) {
 
 	/* If we don't have enough data give up */
 	if ( len < NBI_HEADER_LENGTH ) {
-		errno = EBADIMG;
+		errno = ENOEXEC;
 		return 0;
 	}
 	
@@ -305,7 +305,7 @@ static int nbi_load ( physaddr_t start, off_t len, void *context ) {
  * @v imgheader		Image header information
  * @ret Never		NBI program booted successfully
  * @ret False		NBI program returned
- * @err EIMGRET		NBI program returned
+ * @err ECANCELED	NBI program returned
  *
  */
 static int nbi_boot16 ( struct imgheader *imgheader ) {
@@ -340,7 +340,7 @@ static int nbi_boot16 ( struct imgheader *imgheader ) {
 		    CLOBBER ( "eax", "ecx", "edx", "ebp" ) );
 	BASEMEM_PARAMETER_DONE ( bootp_data );
 	
-	errno = EIMGRET;
+	errno = ECANCELED;
 	return 0;
 }
 
@@ -350,11 +350,11 @@ static int nbi_boot16 ( struct imgheader *imgheader ) {
  * @v imgheader		Image header information
  * @ret False		NBI program should not have returned
  * @ret other		As returned by NBI program
- * @err EIMGRET		NBI program should not have returned
+ * @err ECANCELED	NBI program should not have returned
  *
  * To distinguish between the case of an NBI program returning false,
  * and an NBI program that should not have returned, check errno.
- * errno will be set to EIMGRET only if the NBI program should not
+ * errno will be set to ECANCELED only if the NBI program should not
  * have returned.
  *
  */
@@ -374,7 +374,7 @@ static int nbi_boot32 ( struct imgheader *imgheader ) {
 	printf ( "Secondary program returned %d\n", rc );
 	if ( ! NBI_PROGRAM_RETURNS ( imgheader->flags ) ) {
 		/* We shouldn't have returned */
-		errno = EIMGRET;
+		errno = ECANCELED;
 		rc = 0;
 	}
 
@@ -388,7 +388,7 @@ static int nbi_boot32 ( struct imgheader *imgheader ) {
  * @ret Never		NBI program booted successfully
  * @ret False		NBI program should not have returned
  * @ret other		As returned by NBI program
- * @err EIMGRET		NBI program should not have returned
+ * @err ECANCELED	NBI program should not have returned
  *
  * See also nbi_boot16() and nbi_boot32().
  *
diff --git a/src/include/errno.h b/src/include/errno.h
index d6ddcc56..32ffe99a 100644
--- a/src/include/errno.h
+++ b/src/include/errno.h
@@ -111,21 +111,61 @@
 
 /*
  * The range 0xd0 to 0xff is defined as "Vendor errors" by the PXE
- * spec.  We place all our Etherboot-specific errors in this range.
- * We also define some generic errors as aliases to the PXE errors.
- *
+ * spec.  We use this space for POSIX-like errors that aren't
+ * accounted for by the (somewhat implementation-specific) PXE error
+ * list.
  */
 
-#define ENOERR		0x00
+#define ENOERR		0x00	/**< Operation completed successfully */
+#define EACCES		0xd0	/**< Permission denied */
+#define EADDRNOTAVAIL	0xd1	/**< Cannot assign requested address */
+#define EADDRINUSE	EADDRNOTAVAIL /**< Address already in use */
+#define EAFNOSUPPORT	0xd2	/**< Address family not supported by protocol*/
+#define EAGAIN		0xd3	/**< Resource temporarily unavailable */
+#define EBUSY		0xd4	/**< Device or resource busy */
+/** Operation cancelled */
+#define ECANCELED	PXENV_STATUS_BINL_CANCELED_BY_KEYSTROKE
+#define ECONNABORTED	0xd5	/**< Software caused connection abort */
+#define ECONNREFUSED	0xd6	/**< Connection refused */
+#define ECONNRESET	0xd7	/**< Connection reset by peer */
+#define EDESTADDRREQ	0xd8	/**< Destination address required */
+#define EFBIG		0xd9	/**< File too large */
+#define EHOSTUNREACH	0xda	/**< No route to host */
+#define EINPROGRESS	0xdb	/**< Operation now in progress */
+#define EINTR		0xdc	/**< Interrupted system call */
+#define EINVAL		0xdd	/**< Invalid argument */
+#define EIO		0xde	/**< Input/output error */
+#define EISCONN		0xdf	/**< Transport endpoint is already connected */
+#define EMFILE		0xe0	/**< Too many open files */
+#define EMSGSIZE	0xe1	/**< Message too long */
+#define ENAMETOOLONG	0xe2	/**< File name too long */
+#define ENETDOWN	0xe3	/**< Network is down */
+#define ENETRESET	0xe4	/**< Network dropped connection on reset */
+#define ENETUNREACH	0xe5	/**< Network is unreachable */
+#define ENFILE		EMFILE	/**< Too many open files in system */
+/** Cannot allocate memory */
 #define ENOMEM		PXENV_STATUS_OUT_OF_RESOURCES
-#define	EBADIMG		0xd0
-#define EIMGRET		0xd1
-#define ETIMEDOUT	0xd2
-#define EINVAL		0xd3
-#define ENOENT		0xd4
-#define EAFNOSUPPORT	0xd5
-#define EAGAIN		0xd6
-#define EIO		0xd7
+#define ENOBUFS		ENOMEM	/**< No buffer space available */
+#define ENODATA		0xe6	/**< No data available */
+#define ENODEV		0xe7	/**< No such device */
+#define ENOENT		0xe8	/**< No such file or directory */
+#define ENOEXEC		0xe9	/**< Exec format error */
+#define ENOMSG		ENODATA	/**< No message of the desired type */
+#define ENOSR		0xea	/**< No stream resources */
+#define ENOSTR		0xeb	/**< Not a stream */
+#define ENOSYS		0xec	/**< Function not implemented */
+#define ENOTCONN	0xed	/**< Transport endpoint is not connected */
+#define ENOTSOCK	0xee	/**< Socket operation on non-socket */
+#define EOPNOTSUPP	0xef	/**< Operation not supported */
+#define ENOTSUP		EOPNOTSUPP /**< Not supported */
+#define ENOTTY		0xf0	/**< Inappropriate ioctl for device */
+#define ENXIO		ENODEV	/**< No such device or address */
+#define EPERM		EACCES	/**< Operation not permitted */
+#define EPROTO		0xf1	/**< Protocol error */
+#define EPROTONOSUPPORT	0xf2	/**< Protocol not supported */
+#define EPROTOTYPE	0xf3	/**< Protocol wrong type for socket */
+#define ETIMEDOUT	0xf4	/**< Connection timed out */
+#define EWOULDBLOCK	EAGAIN	/**< Resource temporarily unavailable */
 
 /* Data structures and declarations */