New comment by PaperMountainStudio on void-packages repository

https://github.com/void-linux/void-packages/pull/23541#issuecomment-682017983

Comment:
@aisecat 
> Did you try using the same SD card with void that boots the 64bit Raspberry Pi OS?

yes, it's the same SD card
> make very sure that the mkplatformfs script pulls in the locally built kernel package

I will check this one later. It might be the problem. I tried replacing kernel8.img with the one from RPiOS and it was still stuck at the rainbow screen. When I replace the whole `/boot` with the one from RPiOS, I get past the rainbow screen to kernel panic that says runit exited with error code 1. I don't have nearly enough experience to continue going this route though.

Some details in which our setups we could be different:
- Raspberry Pi 4B 4GB version
- I used the PLATFORMFS tarball (I doubt this makes a difference)
- /boot is vfat
- / is ext4

I don't think any of these details matter. When I have time, I will try building the kernel again and I will make sure it the one in /boot. This seems to be the most likely mistake I made.