i = strlen(lock->lk->filename) - 5; /* .lock */
                lock->lk->filename[i] = 0;
                err = unlink(lock->lk->filename);
-               if (err) {
+               if (err && errno != ENOENT) {
                        ret = 1;
                        error("unlink(%s) failed: %s",
                              lock->lk->filename, strerror(errno));
        tz = strtoul(tz_c, NULL, 10);
        if (get_sha1_hex(logdata, sha1))
                die("Log %s is corrupt.", logfile);
+       if (is_null_sha1(sha1)) {
+               if (get_sha1_hex(logdata + 41, sha1))
+                       die("Log %s is corrupt.", logfile);
+       }
        if (msg)
                *msg = ref_msg(logdata, logend);
        munmap(log_mapped, mapsz);