let me explain further…
I just tried to have a dual boot with 2 Antergos partitions, having a different DE for each. I wanted to have clean install for each of them.
I then plugged in my USB flash drive and started the installation. Cnchi update took place (by the way, with cnchi version 42, I got a message that Cnchi is not up to date despite the update took place). I use the manual partitioning option to install Antergos on an empty partition and mounted my already existing /swap and /boot/efi partitions (without formatting them).
At this point, I might have forgotten to uncheck the grub installation…
The installation ran well in term of downloading everything (Openbox DE) and package installation started until it got stuck on lightdm installation.
So, after a while, I interrupted the installation.
Now, when I start my laptop, I get a first grub window (not Antergos branded) proposing Arch and Arch fallback launch. Selecting Arch brings an error and, after typing a key as proposed, I get the usual Antergos grub and I am able to launch it as I used to.
The issue is now I cannot run Antergos installation from a flash drive anymore (I wanted to reset my installation). The laptop boots on USB but I get only a black screen.
Looking into /boot/efi, I see 2 antergos_efi directories (not exactly the same name). One has the creation date of my 2nd install. I am wondering whether I should remove it to have only one grub and to be able to run Antergos install from USB again. What do you think ? Any other advice ?
Thanks a lot for your support !