--- /sys/src/9k/boot/aux.c
+++ /sys/src/9k/boot/aux.c
@@ -10,7 +10,7 @@ plumb(char *dir, char *dest, int *efd, char *here)
 	char name[128];
 	int n;
 
-	sprint(name, "%s/clone", dir);
+	snprint(name, sizeof name, "%s/clone", dir);
 	efd[0] = open(name, ORDWR);
 	if(efd[0] < 0)
 		return -1;
@@ -20,15 +20,15 @@ plumb(char *dir, char *dest, int *efd, char *here)
 		return -1;
 	}
 	buf[n] = 0;
-	sprint(name, "%s/%s/data", dir, buf);
+	snprint(name, sizeof name, "%s/%s/data", dir, buf);
 	if(here){
-		sprint(buf, "announce %s", here);
+		snprint(buf, sizeof buf, "announce %s", here);
 		if(sendmsg(efd[0], buf) < 0){
 			close(efd[0]);
 			return -1;
 		}
 	}
-	sprint(buf, "connect %s", dest);
+	snprint(buf, sizeof buf, "connect %s", dest);
 	if(sendmsg(efd[0], buf) < 0){
 		close(efd[0]);
 		return -1;
@@ -138,7 +138,7 @@ srvcreate(char *name, int fd)
 	f = create(buf, 1, 0666);
 	if(f < 0)
 		fatal(buf);
-	sprint(buf, "%d", fd);
+	snprint(buf, sizeof buf, "%d", fd);
 	if(write(f, buf, strlen(buf)) != strlen(buf))
 		fatal("write");
 	close(f);
--- /sys/src/9k/boot/bootip.c
+++ /sys/src/9k/boot/bootip.c
@@ -30,7 +30,7 @@ configip(int bargc, char **bargv, int needfs)
 
 	argc = bargc;
 	argv = arg;
-	strcpy(mpoint, "/net");
+	strncpy(mpoint, "/net", sizeof mpoint);
 	ARGBEGIN {
 	case 'x':
 		p = ARGF();