- if (tid != b->core.tid) {
- free(ref);
- ref = fai_fetch(fai, header->target_name[b->core.tid], &len);
- tid = b->core.tid;
+ if (b->core.tid >= 0) {
+ if (tid != b->core.tid) {
+ free(ref);
+ ref = fai_fetch(fai, header->target_name[b->core.tid], &len);
+ tid = b->core.tid;
+ }
+ bam_fillmd1(b, ref, is_equal);