How to program the nRF52840 in the RAK4631 without Arduino Framework?

Hello everyone
I wanted to know, is there a way to program the WisCore microcontroller, without using the arduino framework.

Welcome to the forum @danjmont

You mean to use other BSP’s like Zephyr or Nordic nRF52 SDK?

Yes it is possible, but we do not offer support or guides for it.
You might check on Zephyr’s website, they claim to have full support for the RAK4631, but I never tried it.