Hey yalls, want to share a little problem I experienced on my Fujitsu laptop on here, and possibly get some help or advice on how to deal with it.
I've searched the internet on these sympthoms but alas, not much had I found regarding this particular behavior. In a last attempt, gonna post here and see if one knows something/experienced it, after almost a year of it laying under my bed, dusting and all.
Soo.. Here's the fun story.
One day, I've decided to invite my friend over to install Arch by the wiki manual, mainly just for giggles but also to expose him to the Linux world a bit.
Not to say that I'm all experienced in computers, a noob myself, but have managed to get Arch installed on my now main laptop before, and haven't experienced such a weird thing I'm boutta tell.
But alright, back on track..Well, to install Arch and not risk breaking your main setup, you need something spare to install it on.
And it was oh so convenient, that I had this laptop just laying around, used mainly just to share our laser printer with our home network and an occasional run of a Minecraft server if I felt like it (im changed now luanti ftw), running Fedora Server.
It is a Fujitsu Lifebook S752 with an i5-3320M and 8 gigs of RAM. Not great, not terrible, one could still use it fine for some simple computer stuff, or again, as a server. It's got UEFI too, to clarify. Even a TPM chip one can swap out too.
Well, off we got. Disk swapped, Live USB booted, manual opened, network.. Set up eventually.
We got to set the basics up, partitioned the drive in a basic way, pacstrapped and, i think, chrooted eventually. All seemed fine, and we got to installing the bootloader. We decided to install systemd-boot because why not, so followed a wiki page on it.
There, my memory is a bit bad in what EXACTLY was done, but after seemingly installing it we tried to reboot, but apparently did not set the bootloader correctly, as it only had a reboot to firmware setup option. No matter, I thought, spin the live OS up again and figure it out. But, after we rebooted to boot from our USB again, we saw that.. The boot menu, once populated with, I reckon, a few more default options such as a network boot or a CD boot, was.. Empty, containing only one boot entry.
(picture of the uefi setup not the boot menu)

Linux Boot Manager
And only that.
And no matter if we stuck a Ventoy USB again, tried different ports, and even disconnected all the storage mediums completely and reconnected them back, even plugged in a drive with an installed OS, going as far as installing a new OS with systemd-boot on the same drive in hopes it'll pick up (i no longer remember if the originally installed one was working the second time).
It was still there, and all it gave was either a "Boot device not found" or just a flash of black on selecting it, returning back to the same boot menu after.
Hard drives were recognized by the UEFI, DVD reader, albeit not the original one, spun up and tried to read something, but no action could update the boot entry list, and no OS could be booted from any media now, it seemed. Even ripping out the RTC battery did not help to clear or reinit it somehow, resetting to defaults neither.
Looked on the internet, someone was writing about getting on an EFI shell and the possible roads from there. Skimming through the Setup, found no clues on how to get on it, if there was a built-in one anyways.
Well, saw it's possible to get it by downloading it on a flashdrive and booting from it, but have I mentioned, that an option to boot from a USB is absent, together with network boot? Yep.
So all that seems to be in my paws are options to enter the UEFI setup, a diagnostic screen, a normie friend who only saw Linux in the moments where it seemed to be comically convoluted to even get the basics done, and no real course of action.
So.. I would appreciate some input on this all. Where to look, what could be done and such. If needed, I can provide some details on what I have right now and cooperate, send further pictures.. Anything will help i guess.
Thanks for the time spent, in advance.
