diff --git a/slsDetectorServers/ctbDetectorServer/bin/ctbDetectorServer_developer b/slsDetectorServers/ctbDetectorServer/bin/ctbDetectorServer_developer
index 764bdadaa..e5f92d113 100755
Binary files a/slsDetectorServers/ctbDetectorServer/bin/ctbDetectorServer_developer and b/slsDetectorServers/ctbDetectorServer/bin/ctbDetectorServer_developer differ
diff --git a/slsDetectorServers/ctbDetectorServer/slsDetectorFunctionList.c b/slsDetectorServers/ctbDetectorServer/slsDetectorFunctionList.c
index 3c0d25d7c..e7f914ca1 100644
--- a/slsDetectorServers/ctbDetectorServer/slsDetectorFunctionList.c
+++ b/slsDetectorServers/ctbDetectorServer/slsDetectorFunctionList.c
@@ -94,7 +94,10 @@ void basictests() {
     LOG(logINFOBLUE, ("********* Chip Test Board Virtual Server *********\n"));
 #else
     LOG(logINFOBLUE, ("************* Chip Test Board Server *************\n"));
-    enableBlackfinAMCExternalAccessExtension();
+    initError = enableBlackfinAMCExternalAccessExtension(initErrorMessage);
+    if (initError == FAIL) {
+        return;
+    }
     initError = defineGPIOpins(initErrorMessage);
     if (initError == FAIL) {
         return;
@@ -440,31 +443,30 @@ uint32_t getDetectorIP() {
     return res;
 }
 
-void enableBlackfinAMCExternalAccessExtension() {
+int enableBlackfinAMCExternalAccessExtension(char *mess) {
     unsigned int value;
-    const char *file_path = "/sys/kernel/debug/blackfin/ebiu_amc/EBIU_AMBCTL1";
-
+    const char *file_path = BFIN_AMC_ACCESS_EXTENSION_FNAME;
     FILE *file = fopen(file_path, "r");
     if (!file) {
-        LOG(logERROR, ("Failed to read EBIU_AMBCTL1\n"));
-        return;
+        strcpy(mess, "Failed to enable blackfin AMC access extension. Could "
+                     "not read EBIU_AMBCTL1\n");
+        LOG(logERROR, (mess));
+        return FAIL;
     }
     fscanf(file, "%x", &value);
     fclose(file);
 
-    // enable support for ARDY signal on interface to FPGA
-    // needed to properly translate avalon_mm_waitrequest in the CTB firmware
-    // https://www.analog.com/media/en/dsp-documentation/processor-manuals/bf537_hwr_Rev3.2.pdf
-    // page 274
-    value |= 0x3;
-
+    value |= BFIN_AMC_ACCESS_EXTENSION_ENA_VAL;
     file = fopen(file_path, "w");
     if (!file) {
-        LOG(logERROR, ("Failed to enable blackfin AMC access extension\n"));
-        return;
+        strcpy(mess, "Failed to enable blackfin AMC access extension. Could "
+                     "not write EBIU_AMBCTL1\n");
+        LOG(logERROR, (mess));
+        return FAIL;
     }
     fprintf(file, "0x%x", value);
     fclose(file);
+    return OK;
 }
 
 /* initialization */
diff --git a/slsDetectorServers/ctbDetectorServer/slsDetectorServer_defs.h b/slsDetectorServers/ctbDetectorServer/slsDetectorServer_defs.h
index 683338861..103502f1f 100644
--- a/slsDetectorServers/ctbDetectorServer/slsDetectorServer_defs.h
+++ b/slsDetectorServers/ctbDetectorServer/slsDetectorServer_defs.h
@@ -7,11 +7,9 @@
 #define MIN_REQRD_VRSN_T_RD_API 0x181130
 #define REQRD_FRMWR_VRSN        0x230705
 
-#define NUM_HARDWARE_VERSIONS (1)
-#define HARDWARE_VERSION_NUMBERS                                               \
-    { 0x3f }
-#define HARDWARE_VERSION_NAMES                                                 \
-    { "5.1" }
+#define NUM_HARDWARE_VERSIONS    (1)
+#define HARDWARE_VERSION_NUMBERS {0x3f}
+#define HARDWARE_VERSION_NAMES   {"5.1"}
 
 #define LINKED_SERVER_NAME "ctbDetectorServer"
 
diff --git a/slsDetectorServers/slsDetectorServer/include/blackfin.h b/slsDetectorServers/slsDetectorServer/include/blackfin.h
index fef76ad48..672f58c57 100644
--- a/slsDetectorServers/slsDetectorServer/include/blackfin.h
+++ b/slsDetectorServers/slsDetectorServer/include/blackfin.h
@@ -5,6 +5,23 @@
 #include <inttypes.h>
 #include <sys/types.h>
 
+/** enable support for ARDY signal on interface to FPGA
+ * needed to properly translate avalon_mm_waitrequest in the CTB firmware
+ * https://www.analog.com/media/en/dsp-documentation/processor-manuals/bf537_hwr_Rev3.2.pdf
+ * page 274
+ * */
+#define BFIN_EBIU_AMBCTL1_B2_ARDY_ENA_OFST (0)
+#define BFIN_EBIU_AMBCTL1_B2_ARDY_ENA_MSK                                      \
+    (1 << BFIN_EBIU_AMBCTL1_B2_ARDY_ENA_OFST)
+#define BFIN_EBIU_AMBCTL1_B2_ARDY_POL_OFST (1)
+#define BFIN_EBIU_AMBCTL1_B2_ARDY_POL_MSK                                      \
+    (1 << BFIN_EBIU_AMBCTL1_B2_ARDY_POL_OFST)
+
+#define BFIN_AMC_ACCESS_EXTENSION_ENA_VAL                                      \
+    (BFIN_EBIU_AMBCTL1_B2_ARDY_ENA_MSK | BFIN_EBIU_AMBCTL1_B2_ARDY_POL_MSK)
+#define BFIN_AMC_ACCESS_EXTENSION_FNAME                                        \
+    "/sys/kernel/debug/blackfin/ebiu_amc/EBIU_AMBCTL1"
+
 /** I2C defines */
 #define I2C_CLOCK_MHZ (131.25)
 
diff --git a/slsDetectorServers/slsDetectorServer/include/slsDetectorFunctionList.h b/slsDetectorServers/slsDetectorServer/include/slsDetectorFunctionList.h
index 80bad5898..8570456f3 100644
--- a/slsDetectorServers/slsDetectorServer/include/slsDetectorFunctionList.h
+++ b/slsDetectorServers/slsDetectorServer/include/slsDetectorFunctionList.h
@@ -113,6 +113,10 @@ void setModuleId(int modid);
 u_int64_t getDetectorMAC();
 u_int32_t getDetectorIP();
 
+#if defined(CHIPTESTBOARDD)
+int enableBlackfinAMCExternalAccessExtension(char *mess);
+#endif
+
 // initialization
 void initControlServer();
 void initStopServer();
@@ -135,7 +139,6 @@ void setupDetector();
 #if defined(CHIPTESTBOARDD)
 int updateDatabytesandAllocateRAM();
 void updateDataBytes();
-void enableBlackfinAMCExternalAccessExtension();
 #endif
 
 #if !defined(CHIPTESTBOARDD) && !defined(XILINX_CHIPTESTBOARDD)
diff --git a/slsSupportLib/include/sls/versionAPI.h b/slsSupportLib/include/sls/versionAPI.h
index b9a1d824d..5b991f4f1 100644
--- a/slsSupportLib/include/sls/versionAPI.h
+++ b/slsSupportLib/include/sls/versionAPI.h
@@ -3,10 +3,10 @@
 /** API versions */
 #define APILIB       "developer 0x241122"
 #define APIRECEIVER  "developer 0x241122"
-#define APICTB       "developer 0x250310"
 #define APIGOTTHARD2 "developer 0x250310"
 #define APIMOENCH    "developer 0x250310"
 #define APIEIGER     "developer 0x250310"
 #define APIXILINXCTB "developer 0x250311"
 #define APIJUNGFRAU  "developer 0x250318"
 #define APIMYTHEN3   "developer 0x250409"
+#define APICTB "developer 0x250519"