@darkcyberman You could be missing dependencies; compare your kernel with GENERIC, LINT, & NOTES.
There is "/boot/kernel.old/kernel" to boot previous kernel (would be useful only if that was the working version & had not installed your non-working version more than once). It can be loaded during boot (do not remember the process).
If you are using #ZFS on root, you may have the option to choose previous "#BootEnvironment" -- option is available from the boot menu.
