diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index 2c172122..28beb76e 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -69,7 +69,6 @@ jobs:
       env:
         AGNOS_UPDATE_URL: https://raw.githubusercontent.com/commaai/ci-artifacts/agnos-builder/pr-${{ github.event.number }}/
       run: |
-        sudo apt-get install -y android-sdk-libsparse-utils
         scripts/package_ota.py
 
     - name: Copy and push boot, system and agnos.json
diff --git a/scripts/package_ota.py b/scripts/package_ota.py
index a03ea21b..8334bd7e 100755
--- a/scripts/package_ota.py
+++ b/scripts/package_ota.py
@@ -5,7 +5,6 @@
 import subprocess
 from copy import deepcopy
 from pathlib import Path
-from tempfile import NamedTemporaryFile
 
 ROOT = Path(__file__).parent.parent
 OUTPUT_DIR = ROOT / "output"
@@ -32,12 +31,12 @@ def process_file(fn, name, sparse=False, full_check=True, has_ab=True, alt=None)
   print(f"  {size} bytes, hash {hash}")
 
   if sparse:
-    with NamedTemporaryFile() as tmp_f:
-      print("  converting sparse image to raw")
-      subprocess.check_call(["simg2img", fn, tmp_f.name])
-      hash_raw = checksum(tmp_f.name)
-      size = Path(tmp_f.name).stat().st_size
-      print(f"  {size} bytes, hash {hash} (raw)")
+    raw_img = OUTPUT_DIR / "system.raw.img"
+    if raw_img.exists():
+      print("  using existing raw image")
+      hash_raw = checksum(raw_img)
+      size = raw_img.stat().st_size
+    print(f"  {size} bytes, hash {hash_raw} (raw)")
 
   print("  compressing")
   xz_fn = OTA_OUTPUT_DIR / f"{fn.stem}-{hash_raw}.img.xz"