Raspberry Pi port, piCore-15.0 is available!
$ flatpak install --user flathub org.libretro.RetroArcherror: GPG signatures found, but none are in trusted keyring
$ tce-load -i flatpak-gir$ flatpak remote-add --user --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo$ flatpak install --user flathub org.libretro.RetroArchRequired runtime for org.libretro.RetroArch/x86_64/stable (org.freedesktop.Platform/x86_64/1.6) is not installed, searching...Found in remote flathub, do you want to install it? [y/n]: yInstalling: org.freedesktop.Platform/x86_64/1.6 from flathub[####################] 11 delta parts, 81 loose fetched; 141011 KiB transferred in 202 secondsInstalling: org.freedesktop.Platform.Locale/x86_64/1.6 from flathub[####################] 3 metadata, 1 content objects fetched; 14 KiB transferred in 0 secondsInstalling: org.libretro.RetroArch/x86_64/stable from flathub[####################] 4 delta parts, 33 loose fetched; 114054 KiB transferred in 163 secondspivot_root: Invalid argument
$ flatpak run org.libretro.RetroArchpivot_root: Invalid argument
initrd is loaded into ramdisk which is an actual file system.initramfs is not a file system.For initrd pivot_root is used and for initramfs switch_root is used.You can not use pivot_root on an initramfs rootfs, you will get Invalid Argument. You can only pivot real file systems.