diff --git a/src/stdio/vfprintf.c b/src/stdio/vfprintf.c
index 15356f53..50fb55c1 100644
--- a/src/stdio/vfprintf.c
+++ b/src/stdio/vfprintf.c
@@ -559,7 +559,7 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg,
 			if (0) {
 		case 'o':
 			a = fmt_o(arg.i, z);
-			if ((fl&ALT_FORM) && p<z-a+1) prefix+=5, pl=1;
+			if ((fl&ALT_FORM) && p<z-a+1) p=z-a+1;
 			} if (0) {
 		case 'd': case 'i':
 			pl=1;
@@ -574,7 +574,7 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg,
 			a = fmt_u(arg.i, z);
 			}
 			if (xp && p<0) goto overflow;
-			if (p>=0) fl &= ~ZERO_PAD;
+			if (xp) fl &= ~ZERO_PAD;
 			if (!arg.i && !p) {
 				a=z;
 				break;