diff --git a/simgear/io/untar.cxx b/simgear/io/untar.cxx
index cc70c62f..4002b61b 100644
--- a/simgear/io/untar.cxx
+++ b/simgear/io/untar.cxx
@@ -634,7 +634,7 @@ void ArchiveExtractor::extractBytes(const uint8_t* bytes, size_t count)
 			d.reset(new ZipExtractorPrivate(this));
 		}
 		else {
-			SG_LOG(SG_IO, SG_ALERT, "Invcalid archive type");
+			SG_LOG(SG_IO, SG_ALERT, "Invalid archive type");
 			_invalidDataType = true;
 			return;
 		}
@@ -724,8 +724,10 @@ ArchiveExtractor::DetermineResult ArchiveExtractor::isTarData(const uint8_t* byt
         }
 
         int result = inflate(&z, Z_SYNC_FLUSH);
-        if (result != Z_OK) {
-            SG_LOG(SG_IO, SG_WARN, "inflate failed:" << result);
+        if ((result == Z_OK) || (result == Z_STREAM_END)) {
+            // all good
+        } else {
+            SG_LOG(SG_IO, SG_WARN, "isTarData: Zlib inflate failed:" << result);
             inflateEnd(&z);
             return Invalid; // not tar data
         }
diff --git a/simgear/package/CatalogTest.cxx b/simgear/package/CatalogTest.cxx
index d901c68f..6dae43f7 100644
--- a/simgear/package/CatalogTest.cxx
+++ b/simgear/package/CatalogTest.cxx
@@ -60,6 +60,7 @@ std::string readFileIntoString(const SGPath& path)
 SGPath global_serverFilesRoot;
 unsigned int global_catalogVersion = 0;
 bool global_failRequests = false;
+bool global_fail747Request = true;
 
 class TestPackageChannel : public TestServerChannel
 {
@@ -97,8 +98,12 @@ public:
         }
 
         if (path == "/catalogTest1/b747.tar.gz") {
-            sendErrorResponse(403, false, "Bad URL");
-            return;
+            if (global_fail747Request) {
+                sendErrorResponse(403, false, "Bad URL");
+                return;
+            } else {
+                path = "/catalogTest1/b747.tar.gz"; // valid path
+            }
         }
         
         localPath.append(path);
@@ -1083,7 +1088,8 @@ void updateInvalidToInvalid(HTTP::Client* cl)
 void testInstallBadPackage(HTTP::Client* cl)
 {
     global_catalogVersion = 0;
-
+    global_fail747Request = true;
+    
     SGPath rootPath(simgear::Dir::current().path());
     rootPath.append("pkg_install_bad_pkg");
     simgear::Dir pd(rootPath);
@@ -1113,15 +1119,29 @@ void testInstallBadPackage(HTTP::Client* cl)
     SG_VERIFY(p1->existingInstall() == ins);
     SG_CHECK_EQUAL(ins->status(), pkg::Delegate::FAIL_DOWNLOAD);
     SG_CHECK_EQUAL(ins->path(), rootPath / "org.flightgear.test.catalog1" / "Aircraft" / "b744");
-}
+    
+    // now retry, it should work
+    global_fail747Request = false;
+    
+    auto ins2 = p1->install();
+    SG_CHECK_EQUAL(ins2, p1->existingInstall());
+    root->scheduleToUpdate(ins2);
+    SG_VERIFY(ins2->isQueued());
 
+    didFail = false;
+    waitForUpdateComplete(cl, root);
+    SG_VERIFY(p1->isInstalled());
+    SG_VERIFY(!didFail);
+    SG_CHECK_EQUAL(ins->status(), pkg::Delegate::STATUS_SUCCESS);
+    SG_CHECK_EQUAL(ins->path(), rootPath / "org.flightgear.test.catalog1" / "Aircraft" / "b744");
+}
 
 int main(int argc, char* argv[])
 {
    // sglog().setLogLevels( SG_ALL, SG_DEBUG );
 
     HTTP::Client cl;
-    cl.setMaxConnections(1);
+    cl.setMaxConnections(1); 
 
     global_serverFilesRoot = SGPath(SRC_DIR);
 
@@ -1156,7 +1176,7 @@ int main(int argc, char* argv[])
     removeInvalidCatalog(&cl);
     
     testVersionMigrateToId(&cl);
-    
+
     testInstallBadPackage(&cl);
     
     SG_LOG(SG_GENERAL, SG_INFO, "Successfully passed all tests!");
diff --git a/simgear/package/catalogTest1/b744/b747-400.xml b/simgear/package/catalogTest1/b744/b747-400.xml
new file mode 100644
index 00000000..a23281ff
--- /dev/null
+++ b/simgear/package/catalogTest1/b744/b747-400.xml
@@ -0,0 +1,7 @@
+<?xml version="1.0"?>
+
+<PropertyList>
+  <sim>
+    <description>Boeing 747-400</description>
+  </sim>
+</PropertyList>
diff --git a/simgear/package/catalogTest1/b747.tar.gz b/simgear/package/catalogTest1/b747.tar.gz
new file mode 100644
index 00000000..ed8e6f1c
Binary files /dev/null and b/simgear/package/catalogTest1/b747.tar.gz differ
diff --git a/simgear/package/catalogTest1/catalog.xml b/simgear/package/catalogTest1/catalog.xml
index 4305b1d1..eb975620 100644
--- a/simgear/package/catalogTest1/catalog.xml
+++ b/simgear/package/catalogTest1/catalog.xml
@@ -215,8 +215,8 @@
           <cockpit type="int">4</cockpit>
         </rating>
 
-        <md5>a94ca5704f305b90767f40617d194ed6</md5>
-        <!-- this URL will fail, on purpose -->
+        <md5>4d3f7417d74f811aa20ccc4f35673d20</md5>
+        <!-- this URL will sometimes fail, on purpose -->
         <url>http://localhost:2000/catalogTest1/b747.tar.gz</url>
       </package>