I imported the OVA image, converted the partition table to GUID, and then formatted the RouterOS Boot partition with FAT16.
After that, I copy the EFI file to /EFI/BOOT/BOOTX64.EFI manually.
It seems that ESXi can actually load the bootloader, but the bootloader can't find the OS. It says "error: could not find disk \n please attach it somewhere else".
Is there any way to patch the EFI file to make it bootable, or is something wrong with my operation?