I surprisedly notice that OpenCore UEFI option has gone away after "reset NVRAM" option was selected. To solve that, you should prepare an empty USB formatted in FAT32.

Access to UEFI Shell

  1. Create a dictionary on the USB Device: /EFI/BOOT.
  2. Copy the file shell.efi which could be downloaded from this to the directiory created above.
  3. Rename shell.efi to BOOTx64.efi.
  4. Reboot your device and choose the UEFI Shell from boot options of BIOS.

Add A New Boot Record

All following commands should be typed into UEFI Shell which we mentioned above.

  1. Run bcfg boot dump, Boot ID is an arbitrary number as long as it is not conflicted with existed one.
  2. Run map, then find the disk at which Hackintosh was installed. Please be aware that DISK ID has a prefix with FS.
  3. Run bcfg boot add <BOOT ID> <DISK ID>:\EFI\BOOT\BOOTx64.efi OpenCore. Please replace the BOOT ID & DISK ID with yours.