I did compile the .bin file from the branch c50v4-noboot as this contained exactly the same description as seen in your latest link.
I kept on going and at the end I got this file (SelfMade-Archer_C50v4-OpenWrt-blocktrron_c50v4-noboot. Here is the VirusTotal check. This is the sha256
I'll give this a try tonight. As soon as I have some news I'll post.