Slim down the rootfs

modules/packages.nix

@@ -36,7 +36,6 @@
 
   fonts = {
     packages = with pkgs; [
-      fira-code
       nerd-fonts.fira-code
       nerd-fonts.fira-mono
       nerd-fonts.symbols-only

pkgs/build-images.nix

@@ -5,6 +5,19 @@
 }:
 pkgs.writeShellApplication {
   name = "build-pipa-images";
+
+  runtimeInputs = with pkgs; [
+    coreutils
+    util-linux
+    dosfstools
+    btrfs-progs
+    git
+    nixos-install-tools
+    nix
+    jq
+    android-tools
+  ];
+
   text = ''
     set -e
     MNT_DIR="$PWD/mnt"
@@ -14,7 +27,6 @@ pkgs.writeShellApplication {
     mkdir -p "$OUT_DIR"
     mkdir -p "$MNT_DIR"
 
-    # SAFETY NET: Automatically unmount if the script fails or is cancelled
     cleanup() {
       echo "=> Ensuring mounts are released..."
       sync
@@ -28,13 +40,25 @@ pkgs.writeShellApplication {
     echo "=> Wiping old images..."
     rm -f "$OUT_DIR/boot.img" "$OUT_DIR/rootfs.img" "$OUT_DIR/rootfs.sparse.img"
 
-    echo "=> Instantly preallocating blocks via fallocate (1GB Boot, 4GB RootFS)..."
-    ${pkgs.util-linux}/bin/fallocate -l 1G "$OUT_DIR/boot.img"
-    ${pkgs.util-linux}/bin/fallocate -l 4G "$OUT_DIR/rootfs.img"
+    echo "=> Calculating dynamic RootFS size..."
+    CLOSURE_BYTES=$(nix path-info --json -S "${toplevel}" | jq -r '.[].closureSize')
+
+    MARGIN_BYTES=$(( 512 * 1024 * 1024 ))
+    ROOTFS_BYTES=$(( CLOSURE_BYTES + MARGIN_BYTES ))
+
+    CLOSURE_MB=$(( CLOSURE_BYTES / 1024 / 1024 ))
+    ROOTFS_MB=$(( ROOTFS_BYTES / 1024 / 1024 ))
+
+    echo "   System closure size: ''${CLOSURE_MB} MB"
+    echo "   Target RootFS size:  ''${ROOTFS_MB} MB"
+
+    echo "=> Allocating blocks..."
+    fallocate -l 1G "$OUT_DIR/boot.img"
+    truncate -s "$ROOTFS_BYTES" "$OUT_DIR/rootfs.img"
 
     echo "=> Formatting images natively..."
-    ${pkgs.dosfstools}/bin/mkfs.vfat -S 4096 -F 32 -n NIX_BOOT "$OUT_DIR/boot.img"
-    ${pkgs.btrfs-progs}/bin/mkfs.btrfs --sectorsize 4096 -L NIX_ROOT "$OUT_DIR/rootfs.img" -f
+    mkfs.vfat -S 4096 -F 32 -n NIX_BOOT "$OUT_DIR/boot.img"
+    mkfs.btrfs --sectorsize 4096 -L NIX_ROOT "$OUT_DIR/rootfs.img" -f
 
     echo "=> Creating Btrfs subvolumes..."
     sudo mount -t btrfs "$OUT_DIR/rootfs.img" "$MNT_DIR"
@@ -44,12 +68,12 @@ pkgs.writeShellApplication {
     sudo umount "$MNT_DIR"
 
     echo "=> Mounting images in Btrfs sequence..."
-    sudo mount -o subvol=root "$OUT_DIR/rootfs.img" "$MNT_DIR"
+    sudo mount -o subvol=root,compress=zstd:9 "$OUT_DIR/rootfs.img" "$MNT_DIR"
 
     sudo mkdir -p "$MNT_DIR/boot" "$MNT_DIR/nix" "$MNT_DIR/home"
 
-    sudo mount -o subvol=nix "$OUT_DIR/rootfs.img" "$MNT_DIR/nix"
-    sudo mount -o subvol=home "$OUT_DIR/rootfs.img" "$MNT_DIR/home"
+    sudo mount -o subvol=nix,compress=zstd:9 "$OUT_DIR/rootfs.img" "$MNT_DIR/nix"
+    sudo mount -o subvol=home,compress=zstd:9 "$OUT_DIR/rootfs.img" "$MNT_DIR/home"
     sudo mount "$OUT_DIR/boot.img" "$MNT_DIR/boot"
 
     echo "=> Seeding NixOS configuration into the user's home folder..."
@@ -60,24 +84,29 @@ pkgs.writeShellApplication {
     sudo cp -r pkgs "$TARGET_FLAKE_DIR/"
 
     echo "=> Securing permissions and initializing Git repo..."
-
     sudo git -C "$TARGET_FLAKE_DIR" init -b main
     sudo git -C "$TARGET_FLAKE_DIR" add .
     sudo chown -R 1000:100 "$MNT_DIR/home/nixos"
 
     echo "=> Injecting the ARM64 OS and native Bootloader..."
-    sudo SYSTEMD_RELAX_ESP_CHECKS=1 ${pkgs.nixos-install}/bin/nixos-install \
+    sudo SYSTEMD_RELAX_ESP_CHECKS=1 nixos-install \
       --root "$MNT_DIR" \
       --system "${toplevel}" \
       --no-root-passwd \
       --no-channel-copy
 
+    echo "=> Optimizing the Nix store to save space..."
+    sudo nix-store --store "$MNT_DIR" --optimise
+
+    echo "=> Forcing Btrfs recursive compression on all files..."
+    sudo btrfs filesystem defragment -r -v -czstd "$MNT_DIR"
+
     echo "=> Flushing write caches and unmounting cleanly..."
     cleanup
     trap - EXIT
 
     echo "=> Converting RootFS to Android sparse format..."
-    ${pkgs.android-tools}/bin/img2simg "$OUT_DIR/rootfs.img" "$OUT_DIR/rootfs.sparse.img"
+    img2simg "$OUT_DIR/rootfs.img" "$OUT_DIR/rootfs.sparse.img"
 
     echo "Done! 'boot.img' and 'rootfs.sparse.img' are ready for flashing."
   '';

pkgs/kernel.nix

@@ -5,7 +5,6 @@
   runCommand,
   ...
 } @ args: let
-  # 1. Fetch the raw source
   rawSrc = fetchFromGitea {
     domain = "gitea.awroo.fun";
     owner = "romanl";
@@ -14,7 +13,6 @@
     hash = "sha256-ApsnYs38vrKwEbvO0d0c4aqpCRQe5FQ7Aa66U38x8JI=";
   };
 
-  # 2. Create a modified source tree with pipa.config pre-injected
   patchedSrc = runCommand "linux-src-pipa" {} ''
     cp -a ${rawSrc} $out
     chmod -R +w $out
@@ -25,11 +23,10 @@ in
     // {
       version = "6.18.2";
       modDirVersion = "6.18.2";
-
       src = patchedSrc;
-
       defconfig = "defconfig pipa.config";
-
       ignoreConfigErrors = true;
+      stripDebugList = ["vmlinux" "lib/modules"];
+
       extraMeta.branch = "6.18";
     })