diff --git a/build.py b/build.py
index 049343563..daee21afb 100755
--- a/build.py
+++ b/build.py
@@ -1,7 +1,6 @@
 #!/usr/bin/env python3
 
 import os
-import shlex
 import subprocess
 import pathlib
 import platform
@@ -41,8 +40,10 @@ def get_deb_extra_depends() -> str:
     return ""
 
 def system2(cmd):
-    args = cmd if isinstance(cmd, list) else shlex.split(cmd)
-    exit_code = subprocess.call(args)
+    if isinstance(cmd, list):
+        exit_code = subprocess.call(cmd)
+    else:
+        exit_code = subprocess.call(cmd, shell=True)
     if exit_code != 0:
         sys.stderr.write(f"Error occurred when executing: `{cmd}`. Exiting.\n")
         sys.exit(-1)
@@ -618,13 +619,13 @@ def main():
                     'cp res/rustdesk.desktop tmpdeb/usr/share/applications/rustdesk.desktop')
                 system2(
                     'cp res/rustdesk-link.desktop tmpdeb/usr/share/applications/rustdesk-link.desktop')
-                os.system('mkdir -p tmpdeb/etc/rustdesk/')
-                os.system('cp -a res/startwm.sh tmpdeb/etc/rustdesk/')
-                os.system('mkdir -p tmpdeb/etc/X11/rustdesk/')
-                os.system('cp res/xorg.conf tmpdeb/etc/X11/rustdesk/')
-                os.system('cp -a DEBIAN/* tmpdeb/DEBIAN/')
-                os.system('mkdir -p tmpdeb/etc/pam.d/')
-                os.system('cp pam.d/rustdesk.debian tmpdeb/etc/pam.d/rustdesk')
+                system2('mkdir -p tmpdeb/etc/rustdesk/')
+                system2('cp -a res/startwm.sh tmpdeb/etc/rustdesk/')
+                system2('mkdir -p tmpdeb/etc/X11/rustdesk/')
+                system2('cp res/xorg.conf tmpdeb/etc/X11/rustdesk/')
+                system2('cp -a DEBIAN/* tmpdeb/DEBIAN/')
+                system2('mkdir -p tmpdeb/etc/pam.d/')
+                system2('cp pam.d/rustdesk.debian tmpdeb/etc/pam.d/rustdesk')
                 system2('strip tmpdeb/usr/bin/rustdesk')
                 system2('mkdir -p tmpdeb/usr/share/rustdesk')
                 system2('mv tmpdeb/usr/bin/rustdesk tmpdeb/usr/share/rustdesk/')
diff --git a/libs/portable/generate.py b/libs/portable/generate.py
index 7b91bb33f..d8e8c07e9 100755
--- a/libs/portable/generate.py
+++ b/libs/portable/generate.py
@@ -67,7 +67,8 @@ def write_app_metadata(output_folder: str):
     print(f"App metadata has been written to {output_path}")
 
 # Allowlist pattern for valid cargo target triples (e.g. x86_64-unknown-linux-gnu)
-_VALID_TARGET_RE = re.compile(r'^[A-Za-z0-9_\-]+$')
+# and JSON target spec paths (e.g. ./targets/my-target.json)
+_VALID_TARGET_RE = re.compile(r'^[A-Za-z0-9_.\-/\\]+$')
 
 
 def build_portable(output_folder: str, target: str):
@@ -76,7 +77,8 @@ def build_portable(output_folder: str, target: str):
         if not _VALID_TARGET_RE.match(target):
             raise ValueError(
                 f"Invalid --target value {target!r}. "
-                "Only alphanumeric characters, hyphens, and underscores are allowed."
+                "Only alphanumeric characters, hyphens, underscores, dots, "
+                "and path separators (/ or \\) are allowed."
             )
         subprocess.run(["cargo", "build", "--release", "--target", target], check=True)
     else: