diff --git a/mmdebstrap b/mmdebstrap
index 730bd1a..808b67a 100755
--- a/mmdebstrap
+++ b/mmdebstrap
@@ -2865,7 +2865,7 @@ sub run_install() {
                 '--format', '$(URI)', 'Created-By: Packages')
               or error "cannot start apt-get indextargets: $!";
             while (my $uri = <$pipe_apt>) {
-                if ($uri =~ /^https:\/\//) {
+                if ($uri =~ /^(mirror\+)?https:\/\//) {
                     info "https mirror found -- adding apt-transport-https "
                       . "and ca-certificates";
                     # FIXME: support for https is part of apt >= 1.5