All guidance update in my BLOG
http://mmdvm.bi7jta.org/search/label/Firmware_upgrade

This firmware is compiled by BI7JTA, use source code from G4KLX 20180822, synchronize with duplex hotspot Ver 1.4.7 

About MMDVM Repeater board by BI7JTA
http://mmdvm.bi7jta.org/search/label/MMDVM_repeater

G4KLX source code
https://github.com/g4klx/MMDVM

Discuss thread https://www.facebook.com/groups/nano.mmdvm/

de bi7jta