Hi!
Using git version 58ca5b7ae70365c1285b2ea0cb3c3370a8f108a9 of openbsc, plus the patch from the attachment, I was able to do a V1 (FR) call, not only EFR.
The FR pcap file is attached to this mail. I'll also put it to the nanoBTS wiki page, like the EFR capture before. I hope this helps you to decode the voice samples.
Regards, Harald