read syscall can return less bytes then requested - handle this.
This bug is triggered when reading from stdin that comes from remote host

Author: Hai Zaar <haizaar@haizaar.com>

--- mtd-utils-1.2.0/nandwrite.c.orig	2008-12-14 14:56:11.000000000 +0200
+++ mtd-utils-1.2.0/nandwrite.c	2008-12-14 15:11:56.000000000 +0200
@@ -218,6 +218,7 @@
 	int ret, readlen;
 	int oobinfochanged = 0;
 	struct nand_oobinfo old_oobinfo;
+	int readcnt = 0;
 
 	process_options(argc, argv);
 
@@ -405,12 +406,22 @@
 		}
 
 		/* Read Page Data from input file */
-		if ((cnt = read(ifd, writebuf, readlen)) != readlen) {
-			if (cnt == 0)	// EOF
-				break;
-			perror ("File I/O error on input file");
-			goto closeall;
+		readcnt = 0;
+		while (readcnt < readlen) {
+			if ((cnt = read(ifd, writebuf + readcnt, readlen - readcnt)) < 0) {
+				perror ("File I/O error on input file");
+				goto closeall;
+			} else {
+				if ((cnt == 0) && (readcnt == 0)) {	// EOF
+					break;
+				} else {
+					readcnt += cnt;
+				}
+			}
+
 		}
+		if ((cnt == 0) && (readcnt == 0))	// EOF
+			break;
 
 		if (writeoob) {
 			/* Read OOB data from input file, exit on failure */