diff --git a/.github/workflows/regtest.yml b/.github/workflows/regtest.yml
index df6f7a2..a258f75 100644
--- a/.github/workflows/regtest.yml
+++ b/.github/workflows/regtest.yml
@@ -3,7 +3,7 @@
 name: Regression Test
 on:
   push:
-    branches: [main]
+    branches: [main, update-tests]
 
 jobs:
   regtest:
diff --git a/oneshot/runtime.py b/oneshot/runtime.py
index 1b4d54a..c2f3ba2 100644
--- a/oneshot/runtime.py
+++ b/oneshot/runtime.py
@@ -66,9 +66,21 @@ class RuntimeInfo:
         """
         with open(self.file_path, "rb") as f:
             data = f.read(16 * 1024 * 1024)
-        cur = data.index(b"pyarmor-vax")
+        cur = data.find(b"pyarmor-vax")
+        if cur == -1:
+            # Specially, check UPX (GH-12, GH-35)
+            if data.find(b"UPX!") != -1 and data.find(b"UPX0") != -1:
+                logger.error(
+                    f"{self.file_path} seems to be packed by UPX. Before it can be processed, you need to unpack it first: Download UPX from https://github.com/upx/upx, and run `upx -d {self.file_path}` (you may need to escape the file path) in the command line."
+                )
+            else:
+                logger.error(
+                    f"{self.file_path} does not contain 'pyarmor-vax'. Maybe it's packed, obfuscated, or generated by an unsupported version of Pyarmor."
+                )
+            raise ValueError(f"{self.file_path} does not contain 'pyarmor-vax'")
 
         if data[cur + 11 : cur + 18] == b"\x00" * 7:
+            # Do not log. Skip this file silently and find another.
             raise ValueError(f"{self.file_path} is a runtime template")
 
         # Align with pyd file and executable address:
@@ -78,7 +90,7 @@ class RuntimeInfo:
 
         if data[0x5C] & 1 != 0:
             logger.error(
-                'External key file ".pyarmor.ikey" is not supported yet, but it will be supported once we get a sample (like this one). Please open an issue on https://github.com/Lil-House/Pyarmor-Static-Unpack-1shot/issues to make this tool stronger.'
+                f'External key file ".pyarmor.ikey" is not supported yet, but it will be supported once we get a sample (like this one). Please open an issue on https://github.com/Lil-House/Pyarmor-Static-Unpack-1shot/issues to make this tool stronger. ({self.file_path})'
             )
             raise NotImplementedError(f'{self.file_path} uses ".pyarmor.ikey"')