diff --git a/stand/kboot/util.c b/stand/kboot/util.c
index 938aad599e19..7d467a29b059 100644
--- a/stand/kboot/util.c
+++ b/stand/kboot/util.c
@@ -1,46 +1,46 @@
 /*-
  * Copyright 2022 Netflix, Inc
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #include "stand.h"
 #include "host_syscall.h"
 #include "kboot.h"
 
 bool
 file2str(const char *fn, char *buffer, size_t buflen)
 {
 	int fd;
 	ssize_t len;
 
 	fd = host_open(fn, HOST_O_RDONLY, 0);
 	if (fd == -1)
 		return false;
 	len = host_read(fd, buffer, buflen - 1);
 	if (len < 0) {
 		host_close(fd);
 		return false;
 	}
 	buffer[len] = '\0';
 	/*
 	 * Trim trailing white space
 	 */
 	while (isspace(buffer[len - 1]))
 		buffer[--len] = '\0';
 	host_close(fd);
 	return true;
 }
 
 bool
 file2u64(const char *fn, uint64_t *val)
 {
-	unsigned long v;
+	unsigned long long v;
 	char buffer[80];
 
 	if (!file2str(fn, buffer, sizeof(buffer)))
 		return false;
 	v = strtoull(buffer, NULL, 0);	/* XXX check return values? */
 	*val = v;
 	return true;
 }