Actually, now you don't need a PSP game installed anymore thanks to this nifty homebrew: https://gbatemp.net/threads/psp-bubble-installer-for-adrenaline-ark-no-ps3-psn.459931/
Just install the Bubble installer, follow the instructions, and then run the easy Adrenaline installer again to have it boot from the bubble created by that homebrew instead of your game.
EDIT: Also, there is a need for the PSP game, as that's how Adrenaline loads. It has to hook into the PSPEmu from a running PSP game or demo.
Understood. Thanks Tom.
Btw, back to the ps1 pkgs, i've found the "idu-mode.vpk" already but not the PKG installer. Next I don't know how to install the IDU app.
I'm following that mini tutorial again.