diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3ff9873d..32d5743b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -24,7 +24,7 @@ endif()
 
 # Define project
 project(ReadoutCard
-  VERSION 0.45.6
+  VERSION 0.45.7
   DESCRIPTION "O2 ReadoutCard library"
   LANGUAGES C CXX
 )
diff --git a/doc/releaseNotes.md b/doc/releaseNotes.md
index c7ad2a23..518eaddc 100644
--- a/doc/releaseNotes.md
+++ b/doc/releaseNotes.md
@@ -90,3 +90,6 @@ This file describes the main feature changes for released versions of ReadoutCar
 
 ## v0.45.6 - 07/02/2025
 - Updated list of firmwares.
+
+## v0.45.7 - 13/03/2025
+- o2-roc-config: added (temporary) option --test-mode-ORC501 to enable testing of new firmware as described in [ORC-501](https://its.cern.ch/jira/browse/ORC-501).
diff --git a/src/CommandLineUtilities/ProgramConfig.cxx b/src/CommandLineUtilities/ProgramConfig.cxx
index c2fbb1a2..bca58c58 100644
--- a/src/CommandLineUtilities/ProgramConfig.cxx
+++ b/src/CommandLineUtilities/ProgramConfig.cxx
@@ -36,6 +36,14 @@ namespace po = boost::program_options;
 
 std::string cmd; // program command invoked
 
+namespace o2
+{
+namespace roc
+{
+extern bool testModeORC501; // testMode flag used for some FW dev, cf JIRA ORC-501
+}
+}
+
 /// Get a status report of given card
 std::string getStatusReport(Parameters::CardIdType cardId)
 {
@@ -322,6 +330,9 @@ class ProgramConfig : public Program
     options.add_options()("drop-bad-rdh",
                           po::bool_switch(&mOptions.dropBadRdhEnabled),
                           "Flag to enable dropping of packets with bad RDH");
+    options.add_options()("test-mode-ORC501",
+                          po::bool_switch(&o2::roc::testModeORC501),
+                          "Flag to enable test mode as described in JIRA ORC-501");
     Options::addOptionCardId(options);
   }
 
diff --git a/src/Cru/CruBar.cxx b/src/Cru/CruBar.cxx
index 5ff90329..a966bd01 100644
--- a/src/Cru/CruBar.cxx
+++ b/src/Cru/CruBar.cxx
@@ -39,6 +39,8 @@ namespace o2
 namespace roc
 {
 
+bool testModeORC501 = false; // testMode flag used for some FW dev, cf JIRA ORC-501
+
 using Link = Cru::Link;
 
 CruBar::CruBar(const Parameters& parameters, std::unique_ptr<RocPciDevice> rocPciDevice)
@@ -776,9 +778,14 @@ void CruBar::configure(bool force)
     }
 
     if (mGbtEnabled /*|| !checkClockConsistent(reportInfo.linkMap)*/) {
+      if (testModeORC501) {
+        log("GBT :  using test mode, cf JIRA ORC-501", LogInfoDevel_(4601));
+      }
       Gbt gbt = Gbt(mPdaBar, mLinkMap, mWrapperCount, mEndpoint);
       gbt.calibrateGbt(mLinkMap);
-      Cru::fpllref(mLinkMap, mPdaBar, 2);
+      if (!testModeORC501) { // testMode flag used for some FW dev, cf JIRA ORC-501
+        Cru::fpllref(mLinkMap, mPdaBar, 2);
+      }
       Cru::fpllcal(mLinkMap, mPdaBar);
       gbt.resetFifo();
     }
diff --git a/src/Cru/Gbt.cxx b/src/Cru/Gbt.cxx
index 442abd31..3fbc35f5 100644
--- a/src/Cru/Gbt.cxx
+++ b/src/Cru/Gbt.cxx
@@ -84,7 +84,10 @@ void Gbt::calibrateGbt(std::map<int, Link> linkMap)
 {
   //Cru::fpllref(linkMap, mPdaBar, 2); //Has been bound with clock configuration
   //Cru::fpllcal(linkMap, mPdaBar); //same
-  cdrref(linkMap, 2);
+  extern bool testModeORC501; // testMode flag used for some FW dev, cf JIRA ORC-501
+  if (!testModeORC501) { // testMode flag used for some FW dev, cf JIRA ORC-501
+    cdrref(linkMap, 2);
+  }
   txcal(linkMap);
   rxcal(linkMap);
 }
diff --git a/src/ReadoutCardVersion.cxx b/src/ReadoutCardVersion.cxx
index 0257d1ba..03977c6c 100644
--- a/src/ReadoutCardVersion.cxx
+++ b/src/ReadoutCardVersion.cxx
@@ -11,7 +11,7 @@
 
 #include "ReadoutCard/Version.h"
 
-#define O2_READOUTCARD_VERSION "0.45.6"
+#define O2_READOUTCARD_VERSION "0.45.7"
 
 namespace o2
 {