I solved the problem. For future reference:

- the external serial port does not provide console output for FriendlyWRT and FriendlyCore by default.
- the serial header pins (next to the WAN/eth0 ethernet port) do work. Use a 115200 bps serial terminal.

Why do you want to downgrade? It's not that I want to downgrade, I just want to install FriendlyWRT or OpenWRT and use eMMC memory. In the meantime I found this guide that hopefully will allow me to at least boot OpenWRT: https://gist.github.com/pjobson/95b67bc4f17c2f60278ec40bf15ca99d This remark ...

Hi guys, Just got myself a new NanoPi R1 (combo kit, H3 chip, 8GB eMMC and metal case) and I need some help getting started. I tried following the guide at http://wiki.friendlyarm.com/wiki/index.php/NanoPi_R1, but I'm running into issues. Downloaded nanopi-r1_eflasher_friendlywrt_4.14_armhf_20191230...