diff --git a/src/emucore/CartDetector.cxx b/src/emucore/CartDetector.cxx
index 7a903d25a..523904a62 100755
--- a/src/emucore/CartDetector.cxx
+++ b/src/emucore/CartDetector.cxx
@@ -849,7 +849,7 @@ bool CartDetector::isProbablyX07(const ByteBuffer& image, size_t size)
 bool CartDetector::isProbablyPlusROM(const ByteBuffer& image, size_t size)
 {
   // PlusCart uses this pattern to detect a PlusROM
-  static constexpr uInt8 signature[3] = { 0x8d, 0xf0, 0x1f };  // STA $1FF0
+  static constexpr uInt8 signature[3] = { 0x8d, 0xf1, 0x1f };  // STA $1FF1
 
   return searchForBytes(image, size, signature, 3);
 }
diff --git a/src/emucore/PlusROM.cxx b/src/emucore/PlusROM.cxx
index e8e0151f4..f5c78c5e6 100644
--- a/src/emucore/PlusROM.cxx
+++ b/src/emucore/PlusROM.cxx
@@ -24,6 +24,7 @@
 #include "Logger.hxx"
 #include "Version.hxx"
 #include "Settings.hxx"
+#include "CartDetector.hxx"
 
 #if defined(HTTP_LIB_SUPPORT)
   #include "http_lib.hxx"
@@ -238,7 +239,7 @@ bool PlusROM::initialize(const ByteBuffer& image, size_t size)
 
   reset();
 
-  return myIsPlusROM = true;
+  return myIsPlusROM = CartDetector::isProbablyPlusROM(image, size);
 #else
   return myIsPlusROM = false;
 #endif