--- a/src/ideviceinstaller.c

+++ b/src/ideviceinstaller.c

@@ -980,7 +980,7 @@ run_again:

 			char *ibuf = malloc(filesize * sizeof(char));

 			size_t amount = fread(ibuf, 1, filesize, fp);

 			if (amount != filesize) {

-				fprintf(stderr, "ERROR: could not read %ld bytes from %s\n", filesize, filename);

+				fprintf(stderr, "ERROR: could not read %zu bytes from %s\n", filesize, filename);

 				free(filename);

 				res = -1;

 				goto leave_cleanup;