On Sun, Jul 30, 2023 at 07:30:27PM +0200, Karel Lucas said:
Should I keep the (U)EFI partition? And if so, how do I mount the future openBSD root partition to this (U)EFI installation? Are there any other things I should watch out for? I look forward to receiving responses from this community. Sincerely, Karel.
As others have said the OpenBSD installer is able to re-use the entire disk and will install the nessicary components to boot OpenBSD. I'll simply add that you would do well to read and understand the Installation Guide [1] and the INSTALL file for the architecture you are using (likely amd64[2] since you mention EFI) before you attempt the installation, they should answer nearly all of your questions -- even the ones you don't know you have yet.
[1] https://www.openbsd.org/faq/faq4.html [2] https://ftp.openbsd.org/pub/OpenBSD/7.3/amd64/INSTALL.amd64 -- Matthew Ernisse https://www.going-flying.com/