I saw a similar issue (but not sure if it is exactly the same though) and answered it in this thread post:
The thread may still provide valid information, although there are some small differences.
You might consider trying the same fixes, maybe one of them works for you.
But be careful to understand the tips well, otherwise there can be real problems.
And make backups first of anything important you may have in you machine, just in case of problems.
Another precaution is to create a Windows rescue disk, and Antergos installer stick (which you probably already have). They are handy if the boot process needs to be restored.
Let’s look at the tips one by one. Note that you’d try one of the them first, reboot and see if it works. If not, try the next one.
- Update Lenovo’s firmware, unless done already. But if you cannot find the exactly correct firmware, do not update anything else, even if it is almost the same as your model.
- Windows bcdedit may also work.
- Using efibootmgr may work, or not. I’d probably skip this here.
- Replacing Windows efi file may and should work. There you’d replace Windows efi file with Antergos counterpart. But as in the tip, copy the original Windows efi file somewhere safe just in case. You might be able to do the efi copying in Windows, something like:
cd /d E:\EFI move Microsoft\Boot\bootmgfw.efi Microsoft\ copy antergos_grub\grubx64.efi Microsoft\Boot\bootmgfw.efi
In alternative 4, your original (was in E:\EFI\Microsoft\Boot\bootmgfw.efi) Windows efi file is moved to E:\EFI\Microsoft\bootmgfw.efi, and a copy of Antergos efi file is where the Windows efi file was.