diff --git a/tools/mkenvimage.c b/tools/mkenvimage.c
index 5521268..4001d2f 100644
--- a/tools/mkenvimage.c
+++ b/tools/mkenvimage.c
@@ -46,6 +46,13 @@
 
 #define CRC_SIZE sizeof(uint32_t)
 
+#ifdef __MINGW32__
+#define FILE_PERM		(S_IRUSR | S_IWUSR)
+#else
+#define FILE_PERM		(S_IRUSR | S_IWUSR | S_IRGRP |\
+					     S_IWGRP)
+#endif
+
 static void usage(const char *exec_name)
 {
 	fprintf(stderr, "%s [-h] [-r] [-b] [-p <byte>] -s <environment partition size> -o <output> <input file>\n"
@@ -293,8 +300,7 @@
 	if (!bin_filename || strcmp(bin_filename, "-") == 0) {
 		bin_fd = STDOUT_FILENO;
 	} else {
-		bin_fd = creat(bin_filename, S_IRUSR | S_IWUSR | S_IRGRP |
-					     S_IWGRP);
+		bin_fd = creat(bin_filename, FILE_PERM);
 		if (bin_fd == -1) {
 			fprintf(stderr, "Can't open output file \"%s\": %s\n",
 					bin_filename, strerror(errno));