Oh, before I forget:
I use 2 patches for the github code:
1) one patch to exclude the check in bool IsDongleAvailable()
This patch circumvents the missing "-s" option in oeserverd.
(The best solution would be to update oeserverd and fix the part with the string "Create USB key dongle System ID file...")
2) one patch to correct packages in cmake/PluginPackage.cmake
this patch sets arch to ARM64 instead of ARMHF
This is basically the code you used in OpenCPN
IF (CMAKE_SYSTEM_PROCESSOR MATCHES "arm*")
IF (CMAKE_SIZEOF_VOID_P MATCHES "8")
SET (ARCH "arm64")
SET (ARCH "armhf")
If you don't make a deb-package, this particular code is not used anymore. It will probably be something similar in the code where you select the plugin-version. (I haven't found that part yet.)
Hope it saves you some time searching.