diff --git a/src/tools/genVersionHeader.pl b/src/tools/genVersionHeader.pl
index 2466aef6b..a1354e66e 100644
--- a/src/tools/genVersionHeader.pl
+++ b/src/tools/genVersionHeader.pl
@@ -75,7 +75,7 @@ if (!$vcs && -d "$opt_t/.git") { # Git
     # v1-4-abcdef-dirty
     # is 4 commits after tag 'v1' with short hash abcdef
     # with uncommited modifications
-    my $result = `git describe --always --tags --dirty --abbrev=20`;
+    my $result = `git describe --always --tags --dirty --long`;
     chomp $result;
     print "== git describe:\n$result\n==\n" if $opt_v;
     if (!$? && $result ne '') {