GM all!

My issue concerns boot drive choice in BIOS. I currently have two NVME drives installed on the board (not the DIMM.2). Drive 1 is a 4TB Sabrent Rocket Plus Gen 4 & Drive 2 is a 2TB Samsung 970 Evo Gen 3. I used to have the 4TB in my TR rig -- swapped it over and did some driver changes when I went to the 12900 & the z690 Maximus Extreme. It used to boot fine, had some stability issues (prob due to the platform change), but it did boot and operate. A few days ago, I installed a fresh WIN11 system on the 2TB and it's been running very smoothly. The odd part is, I can no longer boot from the 4TB drive. If I boot into BIOS, it shows only the 4TB drive as a boot option, and if I choose it, it will always boot from the 2TB drive -- even though it isn't even an option!!

Both drives show up in BIOS otherwise -- just not in the boot options
MB is z690 Maximus Extreme
CPU 12900K
BIOS has latest FW version
NVME drives are not residing in the slot that shares the CPU PCI lanes -- they are both in the regular chipset slots.

Any ideas?

Thanks so much!!!