GRUB not detecting patched kernel on Void Linux?

I have a Void Linux partition on my MacBook Air. I followed this guide to compile a patched version of Linux 6.3.7_1. I built the kernel in ~/build and everything went well but when I reboot the kernel is not detected as an option, even after running sudo update-grub. What did I do wrong? Update: - I added a custom menuentry. - I’ll edit when I get it working