+sub
+find_fs_uuid_of_device
+{
+ my $dev = shift || die;
+ my $blkid_output = `blkid ${dev}`;
+
+ if ($blkid_output =~ /UUID="([^"]+)"/) {
+ return $1;
+ }
+
+ die("Could not find fs uuid of $dev");
+}
+
+sub
+find_efi_parition
+{
+ my $uuid_in_grub_cfg = shift || die;
+ my @candidates;
+
+ my $efi_parition = undef;
+
+ for (`blkid`) {
+ if (/^([\S]+):.*TYPE="vfat"/) {
+ push(@candidates, $1);
+ }
+ }
+
+ for my $dev (@candidates) {
+ system("mount -o ro $dev /mnt");
+ if (-f $grubcfg) {
+ open(GRUBCFG, '<', $grubcfg) || die ("Can't open $grubcfg: $!");
+ my @lines = <GRUBCFG>;
+ for (@lines) {
+ if (/${uuid_in_grub_cfg}/) {
+ $efi_parition = $dev;
+ }
+ }
+ close(GRUBCFG);
+ }
+ system("umount /mnt");
+ last if defined $efi_parition;
+ }
+
+ die ("No efi parition found") unless defined $efi_parition;
+
+ return $efi_parition;
+}
+
+sub
+generate_fstab
+{
+ my $root_fs_uuid = shift || die;
+ my $efi_fs_uuid = shift || die;
+
+ open(FSTAB, '>', '/etc/fstab') || die ("Can not open fstab");
+ print FSTAB <<EOF;
+UUID="$root_fs_uuid" / ext4 defaults 0 0
+UUID="$efi_fs_uuid" /boot/efi vfat defaults 0 0
+EOF
+ close(FSTAB);
+}
+
+sub
+install_grub
+{
+ system('rm -rf /boot/efi/EFI');
+ system('apt-get install -y grub-efi-arm64-signed-');
+ system("echo 'grub-efi-arm64 grub2/update_nvram boolean false' | debconf-set-selections");
+ system("echo 'grub-efi-arm64 grub2/force_efi_extra_removable boolean true' | debconf-set-selections");
+ system('dpkg-reconfigure -fnoninteractive grub-efi-arm64');
+ system('update-grub');
+ system('grub-install --removable /boot/efi');
+}
+
+sub
+update_wifi_firmware_if_necessary
+{
+ return unless -f $firmware_tarball;
+
+ if (-f $firmware_manifest) {
+ system("sha256sum -c $firmware_manifest --quiet");
+ return if $? == 0;
+ }
+
+ system("sha256sum $firmware_tarball > $firmware_manifest");
+ system("tar -C /lib/firmware/ -xf $firmware_tarball");
+
+ unlink('/etc/modprobe.d/blacklist.conf');
+ system('modprobe brcmfmac');
+}
+
+my $root_block_device = undef;
+my $initial_root_fs_uuid = undef;
+my $efi_block_device = undef;
+my $efi_fs_uuid = undef;
+
+unless (-f '/boot/grub/grub.cfg') {
+ $root_block_device = find_root_device();
+ system("resize2fs $root_block_device");
+ $initial_root_fs_uuid = find_fs_uuid_of_device($root_block_device);
+ $efi_block_device = find_efi_parition($initial_root_fs_uuid);
+ $efi_fs_uuid = find_fs_uuid_of_device($efi_block_device);
+ generate_fstab($initial_root_fs_uuid, $efi_fs_uuid);
+ system('mount /boot/efi');
+ install_grub();
+}