Index: bin/sh/output.c
===================================================================
--- bin/sh/output.c
+++ bin/sh/output.c
@@ -54,6 +54,7 @@
 #include <errno.h>
 #include <unistd.h>
 #include <stdlib.h>
+#include <time.h>
 
 #include "shell.h"
 #include "syntax.h"
@@ -310,9 +311,12 @@
 	int ntry;
 	int i;
 	int n;
+	struct timespec rq;
 
 	n = nbytes;
 	ntry = 0;
+	rq.tv_sec = 0;
+	rq.tv_nsec = 10000000;	/* 10msec */
 	for (;;) {
 		i = write(fd, buf, n);
 		if (i > 0) {
@@ -323,6 +327,11 @@
 		} else if (i == 0) {
 			if (++ntry > 10)
 				return nbytes - n;
+		} else if (errno == EAGAIN) {
+			if (++ntry > 10)
+				return -1;
+			(void)nanosleep(&rq, NULL);
+			continue;
 		} else if (errno != EINTR) {
 			return -1;
 		}