script/public-inbox-init | 4 ++++

diff --git a/script/public-inbox-init b/script/public-inbox-init
index 54d6ce4c11743c7137352379bb6f83c83fa4f8cc..739ec9e55530c3dacdc3c6e9e33df6b099e474a6 100755
--- a/script/public-inbox-init
+++ b/script/public-inbox-init
@@ -63,6 +63,10 @@ my $pfx = "publicinbox.$name";
 my @x = (qw/git config/, "--file=$filename");
 $git_dir = abs_path($git_dir);
 x(qw(git init -q --bare), $git_dir);
+
+# set a reasonable default:
+x(qw/git config/, "--file=$git_dir/config", 'repack.writeBitmaps', 'true');
+
 foreach my $addr (@address) {
 	next if $seen{lc($addr)};
 	x(@x, "--add", "$pfx.address", $addr);