diff --git a/panda/src/downloadertools/apply_patch.cxx b/panda/src/downloadertools/apply_patch.cxx
index 28a10f460f..3626f13c9f 100644
--- a/panda/src/downloadertools/apply_patch.cxx
+++ b/panda/src/downloadertools/apply_patch.cxx
@@ -29,7 +29,7 @@ int
 main(int argc, char *argv[]) {
   if (argc < 3) {
     cerr << "Usage: apply_patch <patch> <file>" << endl;
-    return 0;
+    return 1;
   }
 
   Filename patch = argv[1];
@@ -41,8 +41,10 @@ main(int argc, char *argv[]) {
   Patchfile pfile;
 
   cerr << "Applying patch file " << patch << " to " << file << endl;
-  if (pfile.apply(patch, file) == false)
+  if (pfile.apply(patch, file) == false) {
     cerr << "apply patch failed" << endl;
+    return 1;
+  }
 
-  return 1;
+  return 0;
 }
diff --git a/panda/src/downloadertools/build_patch.cxx b/panda/src/downloadertools/build_patch.cxx
index 081e3186f9..1515f81ca9 100644
--- a/panda/src/downloadertools/build_patch.cxx
+++ b/panda/src/downloadertools/build_patch.cxx
@@ -29,7 +29,7 @@ int
 main(int argc, char *argv[]) {
   if (argc < 3) {
     cerr << "Usage: build_patch <src_file> <dest_file>" << endl;
-    return 0;
+    return 1;
   }
 
   Filename src_file = argv[1];
@@ -42,8 +42,10 @@ main(int argc, char *argv[]) {
 
   cerr << "Building patch file to convert " << src_file << " to "
     << dest_file << endl;
-  if (pfile.build(src_file, dest_file) == false)
+  if (pfile.build(src_file, dest_file) == false) {
     cerr << "build patch failed" << endl;
+    return 1;
+  }
 
-  return 1;
+  return 0;
 }
diff --git a/panda/src/downloadertools/check_adler.cxx b/panda/src/downloadertools/check_adler.cxx
index c4bd19173b..bf9b0949f9 100644
--- a/panda/src/downloadertools/check_adler.cxx
+++ b/panda/src/downloadertools/check_adler.cxx
@@ -22,12 +22,12 @@ int
 main(int argc, char *argv[]) {
   if (argc < 2) {
     cerr << "Usage: check_adler <file>" << endl;
-    return 0;
+    return 1;
   }
 
   Filename source_file = argv[1];
 
   cout << check_adler(source_file);
 
-  return 1;
+  return 0;
 }
diff --git a/panda/src/downloadertools/check_crc.cxx b/panda/src/downloadertools/check_crc.cxx
index 199a285bb0..81367660b8 100644
--- a/panda/src/downloadertools/check_crc.cxx
+++ b/panda/src/downloadertools/check_crc.cxx
@@ -22,12 +22,12 @@ int
 main(int argc, char *argv[]) {
   if (argc < 2) {
     cerr << "Usage: check_crc <file>" << endl;
-    return 0;
+    return 1;
   }
 
   Filename source_file = argv[1];
 
   cout << check_crc(source_file);
 
-  return 1;
+  return 0;
 }
diff --git a/panda/src/downloadertools/check_md5.cxx b/panda/src/downloadertools/check_md5.cxx
index 3681db1de2..1a62c8972c 100644
--- a/panda/src/downloadertools/check_md5.cxx
+++ b/panda/src/downloadertools/check_md5.cxx
@@ -26,7 +26,7 @@ main(int argc, char *argv[]) {
   const char *usagestr="Usage: check_md5 [-dbfmt_output] <file>";
   if (argc < 2) {
     cerr << usagestr << endl;
-    return 0;
+    return 1;
   }
 
   bool bRemoveBrackets = (strcmp("-dbfmt_output",argv[1])==0);
@@ -36,7 +36,7 @@ main(int argc, char *argv[]) {
   if(bRemoveBrackets) {
     if(argc<3) {
         cerr << usagestr << endl;
-        return 0;
+        return 1;
     }
     source_file =  Filename::from_os_specific(argv[2]);
   } else {
@@ -46,7 +46,7 @@ main(int argc, char *argv[]) {
   if(!source_file.exists()) {
        cerr << usagestr << endl;
        cerr << source_file << " not found!\n";
-       return -1;
+       return 2;
   }
 
   HashVal hash;
@@ -60,5 +60,5 @@ main(int argc, char *argv[]) {
 
   cout << hash << endl;
 
-  return 1;
+  return 0;
 }