diff --git a/netwerk/protocol/data/nsDataChannel.cpp b/netwerk/protocol/data/nsDataChannel.cpp
index eb49bfbede11..2b96cb08530e 100644
--- a/netwerk/protocol/data/nsDataChannel.cpp
+++ b/netwerk/protocol/data/nsDataChannel.cpp
@@ -82,7 +82,13 @@ nsresult nsDataChannel::OpenContentStream(bool async, nsIInputStream** result,
   if (lBase64) {
     nsAutoCString decodedData;
     rv = Base64Decode(data, decodedData);
-    NS_ENSURE_SUCCESS(rv, rv);
+    if (NS_FAILED(rv)) {
+      // Returning this error code instead of what Base64Decode returns
+      // (NS_ERROR_ILLEGAL_VALUE) will prevent rendering of redirect response
+      // content by HTTP channels.  It's also more logical error to return.
+      // Here we know the URL is actually corrupted.
+      return NS_ERROR_MALFORMED_URI;
+    }
 
     contentLen = decodedData.Length();
     rv = NS_NewCStringInputStream(getter_AddRefs(bufInStream), decodedData);
diff --git a/netwerk/protocol/http/nsHttpChannel.cpp b/netwerk/protocol/http/nsHttpChannel.cpp
index 242d585a71b4..8e07e43e0d4b 100644
--- a/netwerk/protocol/http/nsHttpChannel.cpp
+++ b/netwerk/protocol/http/nsHttpChannel.cpp
@@ -5617,6 +5617,7 @@ nsresult nsHttpChannel::ContinueProcessRedirection(nsresult rv) {
   } else {
     rv = mRedirectChannel->AsyncOpen(mListener, mListenerContext);
   }
+  LOG(("  new channel AsyncOpen returned %" PRIX32, static_cast<uint32_t>(rv)));
   NS_ENSURE_SUCCESS(rv, rv);
 
   // close down this channel