install to-filesystem fails at bootupd backend install

[p5]

When trying to install a bootc image using "bootc install to-filesystem", bootupd is failing to install the backend configuration with the following error:

| Deploying container image...done (75 seconds)
| Running bootupctl to install bootloader
| > bootupctl backend install --write-uuid --update-firmware --auto --device /dev/vda /tmp/.tmp9cxkgO
| BootCurrent: 0001
| Timeout: 3 seconds
| BootOrder: 0003,0001,0002,0000
| Boot0000* UiAppFvVol(7cb8bdc9-f8eb-4f34-aaea-3ee4af6516a1)/FvFile(462caa21-7614-4503-836e-8ab6f4662331)
| Boot0001* UEFI QEMU DVD-ROM QM00001 PciRoot(0x0)/Pci(0x1f,0x2)/Sata(0,65535,0){auto_created_boot_option}
| Boot0002* UEFI Misc DevicePciRoot(0x0)/Pci(0x2,0x3)/Pci(0x0,0x0){auto_created_boot_option}
| Boot0003* Fedora
| HD(1,GPT,fb81749d-e528-4386-9f03-9aba7c05441c,0x800,0x100000)/\EFI\fedora\shimx64.efi
| Installed: grub.cfg
| error: boot data installation failed: Installing static GRUB configs: Copying static EFI: Invalid argument (os error 22)
| ERROR Installing to filesystem: Installing bootloader: Task Running bootupctl to install bootloader failed: ExitStatus(unix_wait_status(256))

We have already created the required filesystem layout before running the following on the host (note: randomfolder is the path to the desired root):

$ bootc install to-filesystem --source-imgref=containers-storage:ghcr.io/ublue-os/bluefin:41 /tmp/(randomfolder)

With a subvolume on /tmp/rootfs/boot, the installation fails, but with /tmp/rootfs/boot/efi is mounted, the install succeeds.

Specifying --boot-mount-spec (without either /boot or /boot/efi mounted) produces a different error, but doesn't really help us with getting this working:

$ sudo bootc install to-filesystem --boot-mount-spec=UUID=df98c74d-e7f8-44ad-aeb0-eb57928db98b --source-imgref="containers-storage:ghcr.io/ublue-os/bluefin:41" /tmp/.tmpJUZa7c/

...
error: boot data installation failed: installing component EFI: Failed to find ESP device

Please could you help us diagnose the issues we're having here, and let us know the proper usage of the install to-filesystem commands.

@tulilirockz - if I've missed anything, please could you provide more details

[gerblesh]

We changed the EFI partition label to be "EFI-SSSTEM" to help bootupd detect it properly. And now bootc install to-filesystem when run manually works.
The problem arises when running inside of readymade in the bootc_copy function: https://github.com/FyraLabs/readymade/blob/189d48bf2792c5544fa1fd5f983d85d5138db4ca/src/backend/install.rs#L288
It gives an invalid argument when copying the static grub files:

error: boot data installation failed: Installing static GRUB configs: Copying static EFI: Invalid argument (os error 22)
ERROR Installing to filesystem: Installing bootloader: Task Running bootupctl to install bootloader failed: ExitStatus(unix_wait_status(256))

Manually setting up mounts and installing via bootc install to-filesystem seems to work (as shown below). My guess is that we are having issues with the mountpoints in readymade itself, there doesn't seem to be any issues with bootc/bootupd

❯ sudo tree -a /mnt
/mnt
├── boot
│   ├── efi
│   └── lost+found
└── lost+found

❯ lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
loop0    7:0    0  4.7G  1 loop /run/rootfsbase
sr0     11:0    1    5G  0 rom  /run/initramfs/live
zram0  251:0    0  2.8G  0 disk [SWAP]
vda    253:0    0   50G  0 disk 
├─vda1 253:1    0  512M  0 part /var/mnt/boot/efi
├─vda2 253:2    0    2G  0 part /var/mnt/boot
└─vda3 253:3    0 47.5G  0 part /var/mnt

sudo bootc install to-filesystem --source-imgref="containers-storage:ghcr.io/ublue-os/bluefin:beta" /mnt/

(Installs properly when running manually from shell)