diff --git a/tools/copy-to-sha256.py b/tools/copy-to-sha256.py
index ec12fb22..c82974dd 100755
--- a/tools/copy-to-sha256.py
+++ b/tools/copy-to-sha256.py
@@ -11,18 +11,6 @@ import sys
 import io
 
 HASH_LENGTH = 8
-USE_COMPRESSION = True
-
-if USE_COMPRESSION:
-    if sys.version_info >= (3, 14):
-        from compression import zstd
-    else:
-        try:
-            import zstandard as zstd
-        except ImportError:
-            print("Error: zstandard module required when USE_COMPRESSION = True")
-            print("Install with: pip install zstandard")
-            sys.exit(1)
 
 def hash_file(filename) -> str:
     with open(filename, "rb", buffering=0) as f:
@@ -43,23 +31,39 @@ def main():
                                    formatter_class=argparse.RawTextHelpFormatter)
     args.add_argument("from_path", metavar="from", help="from")
     args.add_argument("to_path", metavar="to", help="to")
+    args.add_argument("--zstd", action="store_true", help="Use Zstandard compression")
 
     args = args.parse_args()
 
     from_path = os.path.normpath(args.from_path)
     to_path = os.path.normpath(args.to_path)
 
+    # Import zstd only if compression is requested
+    zstd_module = None
+    if args.zstd:
+        if sys.version_info >= (3, 14):
+            from compression import zstd
+            zstd_module = zstd
+        else:
+            try:
+                import zstandard as zstd
+                zstd_module = zstd
+            except ImportError:
+                print("Error: zstandard module required when using --zstd flag")
+                print("Install with: pip install zstandard")
+                sys.exit(1)
+
     if os.path.isfile(from_path):
         tar = tarfile.open(from_path, "r")
     else:
         tar = None
 
     if tar:
-        handle_tar(logger, tar, to_path)
+        handle_tar(logger, tar, to_path, args.zstd, zstd_module)
     else:
-        handle_dir(logger, from_path, to_path)
+        handle_dir(logger, from_path, to_path, args.zstd, zstd_module)
 
-def handle_dir(logger, from_path: str, to_path: str):
+def handle_dir(logger, from_path: str, to_path: str, use_compression: bool, zstd_module):
     def onerror(oserror):
         logger.warning(oserror)
 
@@ -78,37 +82,37 @@ def handle_dir(logger, from_path: str, to_path: str):
                 continue
 
             file_hash = hash_file(absname)
-            filename = file_hash[0:HASH_LENGTH] + (".bin.zst" if USE_COMPRESSION else ".bin")
+            filename = file_hash[0:HASH_LENGTH] + (".bin.zst" if use_compression else ".bin")
             to_abs = os.path.join(to_path, filename)
 
             if os.path.exists(to_abs):
                 logger.info("Exists, skipped {} ({})".format(to_abs, absname))
             else:
-                if USE_COMPRESSION:
+                if use_compression:
                     logger.info("Compressing {} {}".format(absname, to_abs))
                     with open(absname, 'rb') as src_file:
                         with open(to_abs, 'wb') as dst_file:
-                            zstd.ZstdCompressor(level=3).copy_stream(src_file, dst_file)
+                            zstd_module.ZstdCompressor(level=19).copy_stream(src_file, dst_file)
                 else:
                     logger.info("cp {} {}".format(absname, to_abs))
                     shutil.copyfile(absname, to_abs)
 
-def handle_tar(logger, tar, to_path: str):
+def handle_tar(logger, tar, to_path: str, use_compression: bool, zstd_module):
     for member in tar.getmembers():
         if member.isfile() or member.islnk():
             f = tar.extractfile(member)
             file_hash = hash_fileobj(f)
-            filename = file_hash[0:HASH_LENGTH] + (".bin.zst" if USE_COMPRESSION else ".bin")
+            filename = file_hash[0:HASH_LENGTH] + (".bin.zst" if use_compression else ".bin")
             to_abs = os.path.join(to_path, filename)
 
             if os.path.exists(to_abs):
                 logger.info("Exists, skipped {} ({})".format(to_abs, member.name))
             else:
-                if USE_COMPRESSION:
+                if use_compression:
                     logger.info("Extracted and compressing {} ({})".format(to_abs, member.name))
                     f.seek(0)
                     with open(to_abs, 'wb') as dst_file:
-                        zstd.ZstdCompressor(level=3).copy_stream(f, dst_file)
+                        zstd_module.ZstdCompressor(level=19).copy_stream(f, dst_file)
                 else:
                     logger.info("Extracted {} ({})".format(to_abs, member.name))
                     to_file = open(to_abs, "wb")
diff --git a/tools/docker/alpine/build.sh b/tools/docker/alpine/build.sh
index e6c4c7aa..72edfb8f 100755
--- a/tools/docker/alpine/build.sh
+++ b/tools/docker/alpine/build.sh
@@ -20,10 +20,10 @@ docker export "$CONTAINER_NAME" -o "$OUT_ROOTFS_TAR"
 # https://github.com/iximiuz/docker-to-linux/issues/19#issuecomment-1242809707
 tar -f "$OUT_ROOTFS_TAR" --delete ".dockerenv" || true
 
-../../../tools/fs2json.py --out "$OUT_FSJSON" "$OUT_ROOTFS_TAR"
+../../../tools/fs2json.py --zstd --out "$OUT_FSJSON" "$OUT_ROOTFS_TAR"
 
 # Note: Not deleting old files here
 mkdir -p "$OUT_ROOTFS_FLAT"
-../../../tools/copy-to-sha256.py "$OUT_ROOTFS_TAR" "$OUT_ROOTFS_FLAT"
+../../../tools/copy-to-sha256.py --zstd "$OUT_ROOTFS_TAR" "$OUT_ROOTFS_FLAT"
 
 echo "$OUT_ROOTFS_TAR", "$OUT_ROOTFS_FLAT" and "$OUT_FSJSON" created.
diff --git a/tools/fs2json.py b/tools/fs2json.py
index 59d00bfa..2bf35aab 100755
--- a/tools/fs2json.py
+++ b/tools/fs2json.py
@@ -17,8 +17,6 @@ import tarfile
 
 VERSION = 3
 
-USE_COMPRESSION = True
-
 IDX_NAME = 0
 IDX_SIZE = 1
 IDX_MTIME = 2
@@ -70,6 +68,8 @@ def main():
     args.add_argument("path",
                       metavar="path-or-tar",
                       help="Base path or tar file to include in JSON")
+    args.add_argument("--zstd", action="store_true",
+                      help="Use Zstandard compression")
 
     args = args.parse_args()
 
@@ -81,9 +81,9 @@ def main():
         tar = None
 
     if tar:
-        (root, total_size) = handle_tar(logger, tar)
+        (root, total_size) = handle_tar(logger, tar, args.zstd)
     else:
-        (root, total_size) = handle_dir(logger, path, args.exclude)
+        (root, total_size) = handle_dir(logger, path, args.exclude, args.zstd)
 
     if False:
         # normalize the order of children, useful to debug differences between
@@ -105,7 +105,7 @@ def main():
     logger.info("Creating json ...")
     json.dump(result, args.out, check_circular=False, separators=(',', ':'))
 
-def handle_dir(logger, path, exclude):
+def handle_dir(logger, path, exclude, use_compression):
     path = path + "/"
     exclude = exclude or []
     exclude = [os.path.join("/", os.path.normpath(p)) for p in exclude]
@@ -199,7 +199,7 @@ def handle_dir(logger, path, exclude):
                 obj[IDX_TARGET] = target
             elif isfile:
                 file_hash = hash_file(absname)
-                filename = file_hash[0:HASH_LENGTH] + (".bin.zst" if USE_COMPRESSION else ".bin")
+                filename = file_hash[0:HASH_LENGTH] + (".bin.zst" if use_compression else ".bin")
                 existing = filename_to_hash.get(filename)
                 assert existing is None or existing == file_hash, "Collision in short hash (%s and %s)" % (existing, file_hash)
                 filename_to_hash[filename] = file_hash
@@ -214,7 +214,7 @@ def handle_dir(logger, path, exclude):
 
     return (mainroot, total_size)
 
-def handle_tar(logger, tar):
+def handle_tar(logger, tar, use_compression):
     mainroot = []
     filename_to_hash = {}
     total_size = 0
@@ -242,7 +242,7 @@ def handle_tar(logger, tar):
             obj[IDX_MODE] |= S_IFREG
             f = tar.extractfile(member)
             file_hash = hash_fileobj(f)
-            filename = file_hash[0:HASH_LENGTH] + (".bin.zst" if USE_COMPRESSION else ".bin")
+            filename = file_hash[0:HASH_LENGTH] + (".bin.zst" if use_compression else ".bin")
             existing = filename_to_hash.get(filename)
             assert existing is None or existing == file_hash, "Collision in short hash (%s and %s)" % (existing, file_hash)
             filename_to_hash[filename] = file_hash