diff --git a/slsDetectorServers/slsDetectorServer/src/ALTERA_PLL.c b/slsDetectorServers/slsDetectorServer/src/ALTERA_PLL.c
index 7ed8dbe02..cb59ecd4e 100644
--- a/slsDetectorServers/slsDetectorServer/src/ALTERA_PLL.c
+++ b/slsDetectorServers/slsDetectorServer/src/ALTERA_PLL.c
@@ -327,6 +327,11 @@ int ALTERA_PLL_SetOutputFrequency(int clkIndex, int pllVCOFreqMhz, int value) {
         }
         return (int)temp;
         */
+
+    #if defined(CHIPTESTBOARDD)
+        // wait for firmware to measure the actual frequency
+        usleep(2 * 1000 * 1000);
+    #endif
     return value;
 }
 
diff --git a/slsDetectorServers/slsDetectorServer/src/slsDetectorServer_funcs.c b/slsDetectorServers/slsDetectorServer/src/slsDetectorServer_funcs.c
index 1fa4fe417..58ed51e8c 100644
--- a/slsDetectorServers/slsDetectorServer/src/slsDetectorServer_funcs.c
+++ b/slsDetectorServers/slsDetectorServer/src/slsDetectorServer_funcs.c
@@ -5882,8 +5882,8 @@ int set_clock_frequency(int file_des) {
                         ("retval %s: %d %s\n", modeName, retval,
                          myDetectorType == XILINX_CHIPTESTBOARD ? "kHz"
                                                                 : "MHz"));
-#if !defined(XILINX_CHIPTESTBOARDD)
-                    // XCTB will give the actual frequency, which is not
+#if !defined(XILINX_CHIPTESTBOARDD) && !defined(CHIPTESTBOARDD)
+                    // both CTB's will give the actual frequency, which is not
                     // 100% identical to the set frequency
                     validate(&ret, mess, val, retval, modeName, DEC);
 #endif