Harold,
After you have your out file and transfer to target, OpenWrt needs the package 'libstdcpp6' installed to run it. I use the OpenWrt Firmware Selector to make a firmware image including this and all other packages I desire (e.g. Wireguard - I'm on the East coast; but I recall someone said they wanted a tunnel onthe West Coast).
I use the /etc/config folder to save ampr-ripd and encap.txt (i.e. they can be added to the backup config file). These file directory details are in the wiki example.
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73,
- Lynwood
KB3VWG