You can check for the '/sys/firmware/efi' directory. If it exists, then the system was booted with UEFI, not U-Boot, and doesn't require the separate boot partition. It's my understanding that arm64/generic systems booting UEFI won't require the separate /boot partition, but we would need to confirm this with the vendor. I would expect that UEFI will be able to handle either scenario - separate boot partition or not.
You can check for the '/sys/firmware/efi' directory. If it exists, then the system was booted with UEFI, not U-Boot, and doesn't require the separate boot partition. It's my understanding that arm64/generic systems booting UEFI won't require the separate /boot partition, but we would need to confirm this with the vendor. I would expect that UEFI will be able to handle either scenario - separate boot partition or not.
I have a few comments inline below too.