Why is my 5.12.10-1 kernel failing to boot?

I tried

" ```
qubes-dom0-update kernel-latest-5.12.9* --enablerepo=qubes-dom0-current-testing

which gives "No package kernel-latest-5.12.9* available."

I have not installed the nvidia driver because I never got the 5.12.10-1 kernel to work. I was going to try the nvidia driver once the kernel worked but it hasn't.