Bootloader boots from old OS drive instead of being on the new OS drive

Good day everyone,

I was having issue with an old installation, so I migrated to a new installation on a new drive. I installed Ventura new on a new empty drive. Then had Ventura migrate the app and settings. Once booted, legacy patcher asked if it could patch the new install I booted into. It patched the new install, rebooted and saw the boot screen as per usual, and it had the new OS drive as the default boot installation.

Now, I removed the old drive, and restarted the system, but I don't get my boot launcher, just a black screen. Only when I put back the old drive do I get the boot launcher. Somehow the boot launcher is on the old drive, whilst the new OS is patched. How do I get this straight so I can remove the old drive?

Thanks in advance.