diff --git a/RELEASE.txt b/RELEASE.txt
index 3395b5bd9..57ff96fd4 100755
--- a/RELEASE.txt
+++ b/RELEASE.txt
@@ -85,6 +85,7 @@ This document describes the differences between v7.0.0 and v6.x.x
 - number of storage cells is not updated in teh receiver. done. and also allowing it to be modified in running status
 - refactored memory structure in receiver and listener code (maybe resolves stuck issue, need to check)
 - callback modified to have rx header and not rx header pointer
+- adapted for g2 hdi v2.0. able to set master from server command line, server config file, and client.
 - rx udp socket refactored (maybe resolves getting stuck?)remove check for eiger header and isntead checks for malformed packets for every detector
 -help should not create a new object
 
diff --git a/python/slsdet/detector.py b/python/slsdet/detector.py
index ca841825a..4283132a9 100755
--- a/python/slsdet/detector.py
+++ b/python/slsdet/detector.py
@@ -1479,8 +1479,8 @@ class Detector(CppDetectorApi):
     @element
     def master(self):
         """
-        [Eiger] Sets half module to master and others to slaves.\n
-        [Gotthard][Gotthard2][Mythen3][Eiger] Gets if the current module/ half module is master.
+        [Eiger][Gotthard2] Sets (half) module to master and other(s) to slaves.\n
+        [Gotthard][Gotthard2][Mythen3][Eiger] Gets if the current (half) module is master.
         """
         return self.getMaster()
 
diff --git a/slsDetectorServers/ctbDetectorServer/bin/ctbDetectorServer_developer b/slsDetectorServers/ctbDetectorServer/bin/ctbDetectorServer_developer
index 705e5b90d..096f1c63d 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 d2f416637..976ef486d 100644
--- a/slsDetectorServers/ctbDetectorServer/slsDetectorFunctionList.c
+++ b/slsDetectorServers/ctbDetectorServer/slsDetectorFunctionList.c
@@ -85,17 +85,9 @@ void basictests() {
     initCheckDone = 0;
     memset(initErrorMessage, 0, MAX_STR_LENGTH);
 #ifdef VIRTUAL
-    LOG(logINFOBLUE,
-        ("******** Chip Test Board Virtual Server *****************\n"));
-    if (mapCSP0() == FAIL) {
-        strcpy(initErrorMessage,
-               "Could not map to memory. Dangerous to continue.\n");
-        LOG(logERROR, (initErrorMessage));
-        initError = FAIL;
-    }
-    return;
+    LOG(logINFOBLUE, ("********* Chip Test Board Virtual Server *********\n"));
 #else
-
+    LOG(logINFOBLUE, ("************* Chip Test Board Server *************\n"));
     initError = defineGPIOpins(initErrorMessage);
     if (initError == FAIL) {
         return;
@@ -104,14 +96,15 @@ void basictests() {
     if (initError == FAIL) {
         return;
     }
+#endif
     if (mapCSP0() == FAIL) {
         strcpy(initErrorMessage,
                "Could not map to memory. Dangerous to continue.\n");
-        LOG(logERROR, ("%s\n\n", initErrorMessage));
+        LOG(logERROR, (initErrorMessage));
         initError = FAIL;
         return;
     }
-
+#ifndef VIRTUAL
     // does check only if flag is 0 (by default), set by command line
     if ((!debugflag) && (!updateFlag) &&
         ((checkType() == FAIL) || (testFpga() == FAIL) ||
@@ -122,7 +115,7 @@ void basictests() {
         initError = FAIL;
         return;
     }
-
+#endif
     uint16_t hversion = getHardwareVersionNumber();
     uint16_t hsnumber = getHardwareSerialNumber();
     uint32_t ipadd = getDetectorIP();
@@ -135,7 +128,7 @@ void basictests() {
     if (fwversion >= MIN_REQRD_VRSN_T_RD_API)
         sw_fw_apiversion = getFirmwareAPIVersion();
     LOG(logINFOBLUE,
-        ("************ Chip Test Board Server *********************\n"
+        ("**************************************************\n"
          "Hardware Version:\t\t 0x%x\n"
          "Hardware Serial Nr:\t\t 0x%x\n"
 
@@ -153,6 +146,7 @@ void basictests() {
          (long long int)sw_fw_apiversion, REQRD_FRMWR_VRSN,
          (long long int)client_sw_apiversion));
 
+#ifndef VIRTUAL
     // return if flag is not zero, debug mode
     if (debugflag || updateFlag) {
         return;
diff --git a/slsDetectorServers/eigerDetectorServer/bin/eigerDetectorServer_developer b/slsDetectorServers/eigerDetectorServer/bin/eigerDetectorServer_developer
index e866db31c..a0fda2018 100755
Binary files a/slsDetectorServers/eigerDetectorServer/bin/eigerDetectorServer_developer and b/slsDetectorServers/eigerDetectorServer/bin/eigerDetectorServer_developer differ
diff --git a/slsDetectorServers/eigerDetectorServer/slsDetectorFunctionList.c b/slsDetectorServers/eigerDetectorServer/slsDetectorFunctionList.c
index 54ca07f07..a674babec 100644
--- a/slsDetectorServers/eigerDetectorServer/slsDetectorFunctionList.c
+++ b/slsDetectorServers/eigerDetectorServer/slsDetectorFunctionList.c
@@ -109,7 +109,10 @@ void basictests() {
     memset(initErrorMessage, 0, MAX_STR_LENGTH);
 #ifdef VIRTUAL
     LOG(logINFOBLUE,
-        ("************ EIGER Virtual Server *****************\n\n"));
+        ("************ EIGER Virtual Server ****************\n\n"));
+#else
+    LOG(logINFOBLUE,
+        ("**************** EIGER Server ********************\n\n"));
 #endif
     uint32_t ipadd = getDetectorIP();
     uint64_t macadd = getDetectorMAC();
@@ -119,7 +122,7 @@ void basictests() {
     int64_t client_sw_apiversion = getClientServerAPIVersion();
 
     LOG(logINFOBLUE,
-        ("**************** EIGER Server *********************\n\n"
+        ("**************************************************\n"
          "Detector IP Addr:\t\t 0x%x\n"
          "Detector MAC Addr:\t\t 0x%llx\n"
 
@@ -142,9 +145,7 @@ void basictests() {
         udpDetails[iRxEntry].srcmac = macadd;
     }
 
-#ifdef VIRTUAL
-    return;
-#endif
+#ifndef VIRTUAL
     // return if debugflag is not zero, debug mode
     if (debugflag || updateFlag) {
         return;
@@ -186,6 +187,7 @@ void basictests() {
         return;
     }
     LOG(logINFO, ("Compatibility - success\n"));
+#endif
 }
 
 #ifdef VIRTUAL
diff --git a/slsDetectorServers/gotthard2DetectorServer/RegisterDefs.h b/slsDetectorServers/gotthard2DetectorServer/RegisterDefs.h
index a5a1fb87a..80096497b 100644
--- a/slsDetectorServers/gotthard2DetectorServer/RegisterDefs.h
+++ b/slsDetectorServers/gotthard2DetectorServer/RegisterDefs.h
@@ -100,6 +100,12 @@
 #define CONFIG_VETO_CH_10GBE_ALG_MSK        (0x00000007 << CONFIG_VETO_CH_10GBE_ALG_OFST)
 #define CONFIG_VETO_CH_10GBE_ENBL_OFST      (15)
 #define CONFIG_VETO_CH_10GBE_ENBL_MSK       (0x00000001 << CONFIG_VETO_CH_10GBE_ENBL_OFST)
+#define CONFIG_SLAVE_OFST                   (16)
+#define CONFIG_SLAVE_MSK                    (0x00000001 << CONFIG_SLAVE_OFST)
+#define CONFIG_HDI_MOD_ID_OFST              (17)
+#define CONFIG_HDI_MOD_ID_MSK               (0x00000007 << CONFIG_HDI_MOD_ID_OFST)
+#define CONFIG_FLIP_DATA_STREAM_OFST        (20)
+#define CONFIG_FLIP_DATA_STREAM_MSK         (0x00000001 << CONFIG_FLIP_DATA_STREAM_OFST)
 #define ALGORITHM_HITS_VAL                  (0x0)
 #define ALGORITHM_RAW_VAL                   (0x7)
 
diff --git a/slsDetectorServers/gotthard2DetectorServer/bin/gotthard2DetectorServer_developer b/slsDetectorServers/gotthard2DetectorServer/bin/gotthard2DetectorServer_developer
index a17968377..77acb0cca 100755
Binary files a/slsDetectorServers/gotthard2DetectorServer/bin/gotthard2DetectorServer_developer and b/slsDetectorServers/gotthard2DetectorServer/bin/gotthard2DetectorServer_developer differ
diff --git a/slsDetectorServers/gotthard2DetectorServer/slsDetectorFunctionList.c b/slsDetectorServers/gotthard2DetectorServer/slsDetectorFunctionList.c
index cfa68014a..804a52a81 100644
--- a/slsDetectorServers/gotthard2DetectorServer/slsDetectorFunctionList.c
+++ b/slsDetectorServers/gotthard2DetectorServer/slsDetectorFunctionList.c
@@ -73,7 +73,6 @@ int64_t burstPeriodReg = 0;
 int filterResistor = 0;
 int cdsGain = 0;
 int detPos[2] = {};
-int master = 1;
 
 int isInitCheckDone() { return initCheckDone; }
 
@@ -87,7 +86,10 @@ void basictests() {
     initCheckDone = 0;
     memset(initErrorMessage, 0, MAX_STR_LENGTH);
 #ifdef VIRTUAL
-    LOG(logINFOBLUE, ("******** Gotthard2 Virtual Server *****************\n"));
+    LOG(logINFOBLUE, ("************ Gotthard2 Virtual Server ************\n"));
+#else
+    LOG(logINFOBLUE, ("**************** Gotthard2 Server ****************\n"));
+#endif
     if (mapCSP0() == FAIL) {
         strcpy(initErrorMessage,
                "Could not map to memory. Dangerous to continue.\n");
@@ -95,16 +97,7 @@ void basictests() {
         initError = FAIL;
         return;
     }
-    return;
-#else
-    LOG(logINFOBLUE, ("************ Gotthard2 Server *********************\n"));
-    if (mapCSP0() == FAIL) {
-        strcpy(initErrorMessage,
-               "Could not map to memory. Dangerous to continue.\n");
-        LOG(logERROR, ("%s\n\n", initErrorMessage));
-        initError = FAIL;
-        return;
-    }
+#ifndef VIRTUAL
     // does check only if flag is 0 (by default), set by command line
     if ((!debugflag) && (!updateFlag) &&
         ((validateKernelVersion(KERNEL_DATE_VRSN) == FAIL) ||
@@ -118,7 +111,7 @@ void basictests() {
         initError = FAIL;
         return;
     }
-
+#endif
     uint16_t hversion = getHardwareVersionNumber();
     uint32_t ipadd = getDetectorIP();
     uint64_t macadd = getDetectorMAC();
@@ -129,7 +122,7 @@ void basictests() {
     uint32_t requiredFirmwareVersion = REQRD_FRMWRE_VRSN;
 
     LOG(logINFOBLUE,
-        ("*************************************************\n"
+        ("**************************************************\n"
          "Hardware Version:\t\t 0x%x\n"
 
          "Detector IP Addr:\t\t 0x%x\n"
@@ -146,6 +139,7 @@ void basictests() {
          (long long int)sw_fw_apiversion, requiredFirmwareVersion,
          (long long int)client_sw_apiversion));
 
+#ifndef VIRTUAL
     // return if flag is not zero, debug mode
     if (debugflag || updateFlag) {
         return;
@@ -234,6 +228,7 @@ int testBus() {
 
     int ret = OK;
     u_int32_t addr = DTA_OFFSET_REG;
+    u_int32_t prevValue = bus_r(addr);
     u_int32_t times = 1000 * 1000;
 
     for (u_int32_t i = 0; i < times; ++i) {
@@ -245,7 +240,7 @@ int testBus() {
         }
     }
 
-    bus_w(addr, 0);
+    bus_w(addr, prevValue);
 
     if (ret == OK) {
         LOG(logINFO, ("Successfully tested bus %d times\n", times));
@@ -388,8 +383,9 @@ void initStopServer() {
         }
 #ifdef VIRTUAL
         sharedMemory_setStop(0);
-        // not reading config file (nothing of interest to stop server)
-        if (checkCommandLineConfiguration() == FAIL) {
+        setMaster(OW_MASTER);
+        if (readConfigFile() == FAIL ||
+            checkCommandLineConfiguration() == FAIL) {
             initCheckDone = 1;
             return;
         }
@@ -464,35 +460,15 @@ void setupDetector() {
     setHighVoltage(DEFAULT_HIGH_VOLTAGE);
 
     // check module type attached if not in debug mode
-    {
-        int ret = checkDetectorType();
-        if (checkModuleFlag) {
-            switch (ret) {
-            case -1:
-                sprintf(initErrorMessage,
-                        "Could not get the module type attached.\n");
-                initError = FAIL;
-                LOG(logERROR, ("Aborting startup!\n\n", initErrorMessage));
-                return;
-            case -2:
-                sprintf(initErrorMessage,
-                        "No Module attached! Run server with -nomodule.\n");
-                initError = FAIL;
-                LOG(logERROR, ("Aborting startup!\n\n", initErrorMessage));
-                return;
-            case FAIL:
-                sprintf(initErrorMessage,
-                        "Wrong Module (Not Gotthard2) attached!\n");
-                initError = FAIL;
-                LOG(logERROR, ("Aborting startup!\n\n", initErrorMessage));
-                return;
-            default:
-                break;
-            }
-        } else {
-            LOG(logINFOBLUE,
-                ("In No-Module mode: Ignoring module type. Continuing.\n"));
-        }
+    if (initError == FAIL)
+        return;
+    if (!checkModuleFlag) {
+        LOG(logINFOBLUE, ("In No-Module mode: Ignoring module type...\n"));
+    } else {
+        initError = checkDetectorType(initErrorMessage);
+    }
+    if (initError == FAIL) {
+        return;
     }
 
     // power on chip
@@ -710,8 +686,35 @@ int readConfigFile() {
                         strlen(line) - 1, line));
         memset(command, 0, LZ);
 
+        // master command
+        if (!strncmp(line, "master", strlen("master"))) {
+            int m = -1;
+            // cannot scan values
+            if (sscanf(line, "%s %d", command, &m) != 2) {
+                sprintf(initErrorMessage,
+                        "Could not scan master commands from on-board server "
+                        "config file. Line:[%s].\n",
+                        line);
+                break;
+            }
+            // validations
+            if (m != 0 && m != 1) {
+                sprintf(initErrorMessage,
+                        "Invalid master argument from on-board server "
+                        "config file. Line:[%s].\n",
+                        line);
+                break;
+            }
+            if (setMaster(m == 1 ? OW_MASTER : OW_SLAVE) == FAIL) {
+                sprintf(initErrorMessage,
+                        "Could not set master from config file. Line:[%s].\n",
+                        line);
+                break;
+            }
+        }
+
         // vetoref command
-        if (!strncmp(line, "vetoref", strlen("vetoref"))) {
+        else if (!strncmp(line, "vetoref", strlen("vetoref"))) {
             int igain = 0;
             int value = 0;
 
@@ -957,15 +960,15 @@ int readConfigFile() {
 
 int checkCommandLineConfiguration() {
     if (masterCommandLine != -1) {
-#ifdef VIRTUAL
-        master = masterCommandLine;
-#else
-        initError = FAIL;
-        strcpy(initErrorMessage,
-               "Cannot set Master from command line for this detector. "
-               "Should have been caught before!\n");
-        return FAIL;
-#endif
+        LOG(logINFOBLUE, ("Setting %s from Command Line\n",
+                          (masterCommandLine == 1 ? "Master" : "Slave")));
+        if (setMaster(masterCommandLine == 1 ? OW_MASTER : OW_SLAVE) == FAIL) {
+            initError = FAIL;
+            sprintf(initErrorMessage, "Could not set %s from command line.\n",
+                    (masterCommandLine == 1 ? "Master" : "Slave"));
+            LOG(logERROR, (initErrorMessage));
+            return FAIL;
+        }
     }
     return OK;
 }
@@ -1497,8 +1500,38 @@ int setHighVoltage(int val) {
 
 /* parameters - timing */
 
+int setMaster(enum MASTERINDEX m) {
+    char *master_names[] = {MASTER_NAMES};
+    LOG(logINFOBLUE, ("Setting up as %s in (%s server)\n", master_names[m],
+                      (isControlServer ? "control" : "stop")));
+    int retval = -1;
+    switch (m) {
+    case OW_MASTER:
+        bus_w(CONFIG_REG, bus_r(CONFIG_REG) & ~CONFIG_SLAVE_MSK);
+        isMaster(&retval);
+        if (retval != 1) {
+            LOG(logERROR, ("Could not set master\n"));
+            return FAIL;
+        }
+        break;
+    case OW_SLAVE:
+        bus_w(CONFIG_REG, bus_r(CONFIG_REG) | CONFIG_SLAVE_MSK);
+        isMaster(&retval);
+        if (retval != 0) {
+            LOG(logERROR, ("Could not set slave\n"));
+            return FAIL;
+        }
+        break;
+    default:
+        // hardware settings (do nothing)
+        break;
+    }
+    return OK;
+}
+
 int isMaster(int *retval) {
-    *retval = master;
+    int slave = ((bus_r(CONFIG_REG) & CONFIG_SLAVE_MSK) >> CONFIG_SLAVE_OFST);
+    *retval = (slave == 1 ? 0 : 1);
     return OK;
 }
 
@@ -1950,54 +1983,71 @@ int *getDetectorPosition() { return detPos; }
 
 // Detector Specific
 
-int checkDetectorType() {
+int checkDetectorType(char *mess) {
 #ifdef VIRTUAL
+    setMaster(OW_MASTER);
     return OK;
 #endif
-    LOG(logINFO, ("Checking type of module\n"));
+    LOG(logINFO, ("Checking module type\n"));
     FILE *fd = fopen(TYPE_FILE_NAME, "r");
     if (fd == NULL) {
-        LOG(logERROR,
-            ("Could not open file %s to get type of the module attached\n",
-             TYPE_FILE_NAME));
-        return -1;
+        sprintf(mess,
+                "Could not open file %s to get type of the module attached\n",
+                TYPE_FILE_NAME);
+        return FAIL;
     }
     char buffer[MAX_STR_LENGTH];
     memset(buffer, 0, sizeof(buffer));
     fread(buffer, MAX_STR_LENGTH, sizeof(char), fd);
     fclose(fd);
     if (strlen(buffer) == 0) {
-        LOG(logERROR,
-            ("Could not read file %s to get type of the module attached\n",
-             TYPE_FILE_NAME));
-        return -1;
+        sprintf(mess,
+                "Could not read file %s to get type of the module attached\n",
+                TYPE_FILE_NAME);
+        LOG(logERROR, (mess));
+        return FAIL;
     }
     int type = atoi(buffer);
-    if (type > TYPE_NO_MODULE_STARTING_VAL) {
-        LOG(logERROR,
-            ("No Module attached! Expected %d, %d or %d for Gotthard2, got "
-             "%d\n",
-             TYPE_GOTTHARD2_MODULE_VAL, TYPE_GOTTHARD2_25UM_MASTER_MODULE_VAL,
-             TYPE_GOTTHARD2_25UM_SLAVE_MODULE_VAL, type));
-        return -2;
-    }
-
-    if (abs(type - TYPE_GOTTHARD2_25UM_MASTER_MODULE_VAL) <= TYPE_TOLERANCE) {
-        LOG(logINFOBLUE, ("MASTER 25um Module\n"));
-        master = 1;
-    } else if (abs(type - TYPE_GOTTHARD2_25UM_SLAVE_MODULE_VAL) <=
+    enum MASTERINDEX master = OW_MASTER;
+    if (abs(type - TYPE_GOTTHARD2_25UM_MASTER_HD1_V1_VAL) <= TYPE_TOLERANCE) {
+        LOG(logINFOBLUE, ("MASTER 25um Module (HDI v1.0)\n"));
+    } else if (abs(type - TYPE_GOTTHARD2_25UM_MASTER_HD1_V2_VAL) <=
                TYPE_TOLERANCE) {
-        master = 0;
-        LOG(logINFOBLUE, ("SLAVE 25um Module\n"));
+        LOG(logINFOBLUE, ("MASTER 25um Module (HDI v2.0)\n"));
+    } else if (abs(type - TYPE_GOTTHARD2_25UM_SLAVE_HDI_V1_VAL) <=
+               TYPE_TOLERANCE) {
+        LOG(logINFOBLUE, ("SLAVE 25um Module (HDI v1.0)\n"));
+        master = OW_SLAVE;
+    } else if (abs(type - TYPE_GOTTHARD2_25UM_SLAVE_HDI_V2_VAL) <=
+               TYPE_TOLERANCE) {
+        LOG(logINFOBLUE, ("SLAVE 25um Module (HDI v2.0)\n"));
+        master = OW_SLAVE;
     } else if (abs(type - TYPE_GOTTHARD2_MODULE_VAL) <= TYPE_TOLERANCE) {
-        master = -1;
         LOG(logINFOBLUE, ("50um Module\n"));
+    }
+    // no module or invalid module
+    else if (type > TYPE_NO_MODULE_STARTING_VAL) {
+        sprintf(mess, "No Module attached! Run server with -nomodule.\n");
+        LOG(logERROR, (mess));
+        return FAIL;
     } else {
-        LOG(logERROR,
-            ("Wrong Module attached! Expected %d, %d or %d for Gotthard2, got "
-             "%d\n",
-             TYPE_GOTTHARD2_MODULE_VAL, TYPE_GOTTHARD2_25UM_MASTER_MODULE_VAL,
-             TYPE_GOTTHARD2_25UM_SLAVE_MODULE_VAL, type));
+        sprintf(mess,
+                "Wrong Module attached! Expected %d, %d, %d, %d or %d for "
+                "Gotthard2, got %d\n",
+                TYPE_GOTTHARD2_MODULE_VAL,
+                TYPE_GOTTHARD2_25UM_MASTER_HD1_V1_VAL,
+                TYPE_GOTTHARD2_25UM_SLAVE_HDI_V1_VAL,
+                TYPE_GOTTHARD2_25UM_MASTER_HD1_V2_VAL,
+                TYPE_GOTTHARD2_25UM_SLAVE_HDI_V2_VAL, type);
+        LOG(logERROR, (mess));
+        return FAIL;
+    }
+    bus_w(CONFIG_REG, bus_r(CONFIG_REG) & ~CONFIG_HDI_MOD_ID_MSK);
+    bus_w(CONFIG_REG, bus_r(CONFIG_REG) | ((type << CONFIG_HDI_MOD_ID_OFST) &
+                                           CONFIG_HDI_MOD_ID_MSK));
+    if (setMaster(master) == FAIL) {
+        strcpy(mess, "Could not set to master/slave.");
+        LOG(logERROR, (mess));
         return FAIL;
     }
     return OK;
diff --git a/slsDetectorServers/gotthard2DetectorServer/slsDetectorServer_defs.h b/slsDetectorServers/gotthard2DetectorServer/slsDetectorServer_defs.h
index 543e1ff20..c13f88540 100644
--- a/slsDetectorServers/gotthard2DetectorServer/slsDetectorServer_defs.h
+++ b/slsDetectorServers/gotthard2DetectorServer/slsDetectorServer_defs.h
@@ -3,7 +3,7 @@
 #pragma once
 #include "sls/sls_detector_defs.h"
 
-#define REQRD_FRMWRE_VRSN (0x210527)
+#define REQRD_FRMWRE_VRSN (0x220720)
 #define KERNEL_DATE_VRSN  "Mon May 10 18:00:21 CEST 2021"
 #define ID_FILE           "detid_gotthard2.txt"
 
@@ -31,8 +31,10 @@
 #define ADU_MAX_BITS                          (12)
 #define MAX_FRAMES_IN_BURST_MODE              (2720)
 #define TYPE_GOTTHARD2_MODULE_VAL             (536)
-#define TYPE_GOTTHARD2_25UM_MASTER_MODULE_VAL (683)
-#define TYPE_GOTTHARD2_25UM_SLAVE_MODULE_VAL  (704)
+#define TYPE_GOTTHARD2_25UM_MASTER_HD1_V1_VAL (683)
+#define TYPE_GOTTHARD2_25UM_SLAVE_HDI_V1_VAL  (704)
+#define TYPE_GOTTHARD2_25UM_MASTER_HD1_V2_VAL (723)
+#define TYPE_GOTTHARD2_25UM_SLAVE_HDI_V2_VAL  (747)
 #define TYPE_GOTTHARD2_MODULE_VAL             (536)
 #define TYPE_TOLERANCE                        (5)
 #define TYPE_NO_MODULE_STARTING_VAL           (800)
@@ -146,6 +148,9 @@ enum CLKINDEX {
 
 enum PLLINDEX { READOUT_PLL, SYSTEM_PLL };
 
+enum MASTERINDEX { MASTER_HARDWARE, OW_MASTER, OW_SLAVE };
+#define MASTER_NAMES "hardware (master/slave)", "master", "slave"
+
 /** Chip Definitions */
 #define ASIC_ADDR_MAX_BITS       (4)
 #define ASIC_CURRENT_INJECT_ADDR (0x9)
diff --git a/slsDetectorServers/gotthardDetectorServer/bin/gotthardDetectorServer_developer b/slsDetectorServers/gotthardDetectorServer/bin/gotthardDetectorServer_developer
index 96599022d..35b74f6a3 100755
Binary files a/slsDetectorServers/gotthardDetectorServer/bin/gotthardDetectorServer_developer and b/slsDetectorServers/gotthardDetectorServer/bin/gotthardDetectorServer_developer differ
diff --git a/slsDetectorServers/gotthardDetectorServer/slsDetectorFunctionList.c b/slsDetectorServers/gotthardDetectorServer/slsDetectorFunctionList.c
index 221676690..cef343ba6 100644
--- a/slsDetectorServers/gotthardDetectorServer/slsDetectorFunctionList.c
+++ b/slsDetectorServers/gotthardDetectorServer/slsDetectorFunctionList.c
@@ -82,22 +82,16 @@ void basictests() {
     memset(initErrorMessage, 0, MAX_STR_LENGTH);
 #ifdef VIRTUAL
     LOG(logINFOBLUE, ("******** Gotthard Virtual Server *****************\n"));
+#else
+    LOG(logINFOBLUE, ("**************** Gotthard Server *****************\n"));
+#endif
     if (mapCSP0() == FAIL) {
         strcpy(initErrorMessage,
                "Could not map to memory. Dangerous to continue.\n");
         LOG(logERROR, (initErrorMessage));
         initError = FAIL;
     }
-    return;
-#else
-    if (mapCSP0() == FAIL) {
-        strcpy(initErrorMessage,
-               "Could not map to memory. Dangerous to continue.\n");
-        LOG(logERROR, ("%s\n\n", initErrorMessage));
-        initError = FAIL;
-        return;
-    }
-
+#ifndef VIRTUAL
     // does check only if flag is 0 (by default), set by command line
     if ((!debugflag) && (!updateFlag) &&
         ((checkType() == FAIL) || (testFpga() == FAIL) ||
@@ -108,7 +102,7 @@ void basictests() {
         initError = FAIL;
         return;
     }
-
+#endif
     uint32_t boardrev = getBoardRevision();
     uint32_t ipadd = getDetectorIP();
     uint64_t macadd = getDetectorMAC();
@@ -117,7 +111,7 @@ void basictests() {
     int64_t client_sw_apiversion = getClientServerAPIVersion();
 
     LOG(logINFOBLUE,
-        ("************ Gotthard Server *********************\n"
+        ("**************************************************\n"
          "Board Revision         : 0x%x\n"
 
          "Detector IP Addr       : 0x%x\n"
@@ -134,6 +128,7 @@ void basictests() {
          (long long int)fwversion, (long long int)swversion,
          (long long int)client_sw_apiversion));
 
+#ifndef VIRTUAL
     if (!debugflag || updateFlag) {
         LOG(logINFO, ("Basic Tests - success\n"));
     }
diff --git a/slsDetectorServers/jungfrauDetectorServer/bin/jungfrauDetectorServer_developer b/slsDetectorServers/jungfrauDetectorServer/bin/jungfrauDetectorServer_developer
index d5e74d794..a9225da3d 100755
Binary files a/slsDetectorServers/jungfrauDetectorServer/bin/jungfrauDetectorServer_developer and b/slsDetectorServers/jungfrauDetectorServer/bin/jungfrauDetectorServer_developer differ
diff --git a/slsDetectorServers/jungfrauDetectorServer/slsDetectorFunctionList.c b/slsDetectorServers/jungfrauDetectorServer/slsDetectorFunctionList.c
index 0a4e6fe89..9c9954d7c 100644
--- a/slsDetectorServers/jungfrauDetectorServer/slsDetectorFunctionList.c
+++ b/slsDetectorServers/jungfrauDetectorServer/slsDetectorFunctionList.c
@@ -67,14 +67,9 @@ void basictests() {
     memset(initErrorMessage, 0, MAX_STR_LENGTH);
 #ifdef VIRTUAL
     LOG(logINFOBLUE, ("******** Jungfrau Virtual Server *****************\n"));
-    if (mapCSP0() == FAIL) {
-        strcpy(initErrorMessage,
-               "Could not map to memory. Dangerous to continue.\n");
-        LOG(logERROR, (initErrorMessage));
-        initError = FAIL;
-    }
-    return;
 #else
+    LOG(logINFOBLUE, ("************ Jungfrau Server *********************\n"));
+
     initError = defineGPIOpins(initErrorMessage);
     if (initError == FAIL) {
         return;
@@ -83,14 +78,14 @@ void basictests() {
     if (initError == FAIL) {
         return;
     }
+#endif
     if (mapCSP0() == FAIL) {
         strcpy(initErrorMessage,
                "Could not map to memory. Dangerous to continue.\n");
-        LOG(logERROR, ("%s\n\n", initErrorMessage));
+        LOG(logERROR, (initErrorMessage));
         initError = FAIL;
-        return;
     }
-
+#ifndef VIRTUAL
     // does check only if flag is 0 (by default), set by command line
     if ((!debugflag) && (!updateFlag) &&
         ((checkType() == FAIL) || (testFpga() == FAIL) ||
@@ -101,7 +96,7 @@ void basictests() {
         initError = FAIL;
         return;
     }
-
+#endif
     uint16_t hversion = getHardwareVersionNumber();
     uint16_t hsnumber = getHardwareSerialNumber();
     uint32_t ipadd = getDetectorIP();
@@ -135,6 +130,7 @@ void basictests() {
          (long long int)sw_fw_apiversion, requiredFirmwareVersion,
          (long long int)client_sw_apiversion));
 
+#ifndef VIRTUAL
     // return if flag is not zero, debug mode
     if (debugflag || updateFlag) {
         return;
diff --git a/slsDetectorServers/moenchDetectorServer/bin/moenchDetectorServer_developer b/slsDetectorServers/moenchDetectorServer/bin/moenchDetectorServer_developer
index 862873808..d8ab6b401 100755
Binary files a/slsDetectorServers/moenchDetectorServer/bin/moenchDetectorServer_developer and b/slsDetectorServers/moenchDetectorServer/bin/moenchDetectorServer_developer differ
diff --git a/slsDetectorServers/moenchDetectorServer/slsDetectorFunctionList.c b/slsDetectorServers/moenchDetectorServer/slsDetectorFunctionList.c
index dc8c0d9b8..4d3a9df81 100644
--- a/slsDetectorServers/moenchDetectorServer/slsDetectorFunctionList.c
+++ b/slsDetectorServers/moenchDetectorServer/slsDetectorFunctionList.c
@@ -88,16 +88,9 @@ void basictests() {
     initCheckDone = 0;
     memset(initErrorMessage, 0, MAX_STR_LENGTH);
 #ifdef VIRTUAL
-    LOG(logINFOBLUE,
-        ("******** Moench Detector Virtual Server *****************\n"));
-    if (mapCSP0() == FAIL) {
-        strcpy(initErrorMessage,
-               "Could not map to memory. Dangerous to continue.\n");
-        LOG(logERROR, (initErrorMessage));
-        initError = FAIL;
-    }
-    return;
+    LOG(logINFOBLUE, ("********* Moench Detector Virtual Server *********\n"));
 #else
+    LOG(logINFOBLUE, ("************* Moench Detector Server *************\n"));
 
     initError = defineGPIOpins(initErrorMessage);
     if (initError == FAIL) {
@@ -107,6 +100,7 @@ void basictests() {
     if (initError == FAIL) {
         return;
     }
+#endif
     if (mapCSP0() == FAIL) {
         strcpy(initErrorMessage,
                "Could not map to memory. Dangerous to continue.\n");
@@ -114,7 +108,7 @@ void basictests() {
         initError = FAIL;
         return;
     }
-
+#ifndef VIRTUAL
     // does check only if flag is 0 (by default), set by command line
     if ((!debugflag) && (!updateFlag) &&
         ((checkType() == FAIL) || (testFpga() == FAIL) ||
@@ -125,7 +119,7 @@ void basictests() {
         initError = FAIL;
         return;
     }
-
+#endif
     uint16_t hversion = getHardwareVersionNumber();
     uint16_t hsnumber = getHardwareSerialNumber();
     uint32_t ipadd = getDetectorIP();
@@ -138,7 +132,7 @@ void basictests() {
     if (fwversion >= MIN_REQRD_VRSN_T_RD_API)
         sw_fw_apiversion = getFirmwareAPIVersion();
     LOG(logINFOBLUE,
-        ("************ Moench Detector Server *********************\n"
+        ("**************************************************\n"
          "Hardware Version:\t\t 0x%x\n"
          "Hardware Serial Nr:\t\t 0x%x\n"
 
@@ -156,6 +150,7 @@ void basictests() {
          (long long int)sw_fw_apiversion, REQRD_FRMWR_VRSN,
          (long long int)client_sw_apiversion));
 
+#ifndef VIRTUAL
     // return if flag is not zero, debug mode
     if (debugflag || updateFlag) {
         return;
diff --git a/slsDetectorServers/mythen3DetectorServer/bin/mythen3DetectorServer_developer b/slsDetectorServers/mythen3DetectorServer/bin/mythen3DetectorServer_developer
index 9d33157f0..0d0629659 100755
Binary files a/slsDetectorServers/mythen3DetectorServer/bin/mythen3DetectorServer_developer and b/slsDetectorServers/mythen3DetectorServer/bin/mythen3DetectorServer_developer differ
diff --git a/slsDetectorServers/mythen3DetectorServer/slsDetectorFunctionList.c b/slsDetectorServers/mythen3DetectorServer/slsDetectorFunctionList.c
index 67f35ea67..257f16e0d 100644
--- a/slsDetectorServers/mythen3DetectorServer/slsDetectorFunctionList.c
+++ b/slsDetectorServers/mythen3DetectorServer/slsDetectorFunctionList.c
@@ -82,23 +82,17 @@ void basictests() {
     initCheckDone = 0;
     memset(initErrorMessage, 0, MAX_STR_LENGTH);
 #ifdef VIRTUAL
-    LOG(logINFOBLUE, ("******** Mythen3 Virtual Server *****************\n"));
+    LOG(logINFOBLUE, ("************* Mythen3 Virtual Server *************\n"));
+#else
+    LOG(logINFOBLUE, ("***************** Mythen3 Server *****************\n"));
+#endif
     if (mapCSP0() == FAIL) {
         strcpy(initErrorMessage,
                "Could not map to memory. Dangerous to continue.\n");
         LOG(logERROR, (initErrorMessage));
         initError = FAIL;
     }
-    return;
-#else
-    LOG(logINFOBLUE, ("************ Mythen3 Server *********************\n"));
-    if (mapCSP0() == FAIL) {
-        strcpy(initErrorMessage,
-               "Could not map to memory. Dangerous to continue.\n");
-        LOG(logERROR, ("%s\n\n", initErrorMessage));
-        initError = FAIL;
-        return;
-    }
+#ifndef VIRTUAL
     // does check only if flag is 0 (by default), set by command line
     if ((!debugflag) && (!updateFlag) &&
         ((validateKernelVersion(KERNEL_DATE_VRSN) == FAIL) ||
@@ -110,6 +104,7 @@ void basictests() {
         initError = FAIL;
         return;
     }
+#endif
     uint16_t hversion = getHardwareVersionNumber();
     uint32_t ipadd = getDetectorIP();
     uint64_t macadd = getDetectorMAC();
@@ -121,7 +116,7 @@ void basictests() {
     uint32_t requiredFirmwareVersion = REQRD_FRMWRE_VRSN;
 
     LOG(logINFOBLUE,
-        ("*************************************************\n"
+        ("**************************************************\n"
          "Hardware Version:\t\t 0x%x\n"
 
          "Detector IP Addr:\t\t 0x%x\n"
@@ -138,6 +133,7 @@ void basictests() {
          (long long int)sw_fw_apiversion, requiredFirmwareVersion,
          (long long int)client_sw_apiversion));
 
+#ifndef VIRTUAL
     // return if flag is not zero, debug mode
     if (debugflag || updateFlag) {
         return;
@@ -506,35 +502,15 @@ void setupDetector() {
     setSettings(DEFAULT_SETTINGS);
 
     // check module type attached if not in debug mode
-    {
-        int ret = checkDetectorType();
-        if (checkModuleFlag) {
-            switch (ret) {
-            case -1:
-                sprintf(initErrorMessage,
-                        "Could not get the module type attached.\n");
-                initError = FAIL;
-                LOG(logERROR, ("Aborting startup!\n\n", initErrorMessage));
-                return;
-            case -2:
-                sprintf(initErrorMessage,
-                        "No Module attached! Run server with -nomodule.\n");
-                initError = FAIL;
-                LOG(logERROR, ("Aborting startup!\n\n", initErrorMessage));
-                return;
-            case FAIL:
-                sprintf(initErrorMessage,
-                        "Wrong Module (Not Mythen3) attached!\n");
-                initError = FAIL;
-                LOG(logERROR, ("Aborting startup!\n\n", initErrorMessage));
-                return;
-            default:
-                break;
-            }
-        } else {
-            LOG(logINFOBLUE,
-                ("In No-Module mode: Ignoring module type. Continuing.\n"));
-        }
+    if (initError == FAIL)
+        return;
+    if (!checkModuleFlag) {
+        LOG(logINFOBLUE, ("In No-Module mode: Ignoring module type...\n"));
+    } else {
+        initError = checkDetectorType(initErrorMessage);
+    }
+    if (initError == FAIL) {
+        return;
     }
 
     powerChip(1);
@@ -2095,39 +2071,40 @@ int enableTenGigabitEthernet(int val) {
     return oneG ? 0 : 1;
 }
 
-int checkDetectorType() {
+int checkDetectorType(char *mess) {
 #ifdef VIRTUAL
     return OK;
 #endif
     LOG(logINFO, ("Checking type of module\n"));
     FILE *fd = fopen(TYPE_FILE_NAME, "r");
     if (fd == NULL) {
-        LOG(logERROR,
-            ("Could not open file %s to get type of the module attached\n",
-             TYPE_FILE_NAME));
-        return -1;
+        sprintf(mess,
+                "Could not open file %s to get type of the module attached\n",
+                TYPE_FILE_NAME);
+        return FAIL;
     }
     char buffer[MAX_STR_LENGTH];
     memset(buffer, 0, sizeof(buffer));
     fread(buffer, MAX_STR_LENGTH, sizeof(char), fd);
     fclose(fd);
     if (strlen(buffer) == 0) {
-        LOG(logERROR,
-            ("Could not read file %s to get type of the module attached\n",
-             TYPE_FILE_NAME));
-        return -1;
+        sprintf(mess,
+                "Could not read file %s to get type of the module attached\n",
+                TYPE_FILE_NAME);
+        return FAIL;
     }
     int type = atoi(buffer);
     if (type > TYPE_NO_MODULE_STARTING_VAL) {
-        LOG(logERROR, ("No Module attached! Expected %d for Mythen, got %d\n",
-                       TYPE_MYTHEN3_MODULE_VAL, type));
-        return -2;
+        sprintf(mess, "No Module attached! Run server with -nomodule.\n");
+        LOG(logERROR, (mess));
+        return FAIL;
     }
 
     if (abs(type - TYPE_MYTHEN3_MODULE_VAL) > TYPE_TOLERANCE) {
-        LOG(logERROR,
-            ("Wrong Module attached! Expected %d for Mythen3, got %d\n",
-             TYPE_MYTHEN3_MODULE_VAL, type));
+        sprintf(mess,
+                "Wrong Module attached! Expected %d for Mythen3, got %d\n",
+                TYPE_MYTHEN3_MODULE_VAL, type);
+        LOG(logERROR, (mess));
         return FAIL;
     }
     return OK;
diff --git a/slsDetectorServers/slsDetectorServer/include/slsDetectorFunctionList.h b/slsDetectorServers/slsDetectorServer/include/slsDetectorFunctionList.h
index e8bd5e397..63eccf967 100644
--- a/slsDetectorServers/slsDetectorServer/include/slsDetectorFunctionList.h
+++ b/slsDetectorServers/slsDetectorServer/include/slsDetectorFunctionList.h
@@ -385,8 +385,10 @@ int getADC(enum ADCINDEX ind);
 int setHighVoltage(int val);
 
 // parameters - timing, extsig
-#ifdef EIGERD
+#if defined(EIGERD) || defined(GOTTHARD2D)
 int setMaster(enum MASTERINDEX m);
+#endif
+#ifdef EIGERD
 int setTop(enum TOPINDEX t);
 int isTop(int *retval);
 #endif
@@ -558,7 +560,7 @@ int setDataStream(enum portPosition port, int enable);
 int setPhase(enum CLKINDEX ind, int val, int degrees);
 
 #elif MYTHEN3D
-int checkDetectorType();
+int checkDetectorType(char *mess);
 int powerChip(int on);
 int setPhase(enum CLKINDEX ind, int val, int degrees);
 int getPhase(enum CLKINDEX ind, int degrees);
@@ -574,7 +576,7 @@ int setClockDividerWithTimeUpdateOption(enum CLKINDEX ind, int val,
 int getClockDivider(enum CLKINDEX ind);
 
 #elif GOTTHARD2D
-int checkDetectorType();
+int checkDetectorType(char *mess);
 int powerChip(int on);
 void setDBITPipeline(int val);
 int getDBITPipeline();
diff --git a/slsDetectorServers/slsDetectorServer/src/slsDetectorServer_funcs.c b/slsDetectorServers/slsDetectorServer/src/slsDetectorServer_funcs.c
index ae93ba936..794024016 100644
--- a/slsDetectorServers/slsDetectorServer/src/slsDetectorServer_funcs.c
+++ b/slsDetectorServers/slsDetectorServer/src/slsDetectorServer_funcs.c
@@ -114,7 +114,6 @@ int printSocketReadError() {
 void init_detector() {
     memset(udpDetails, 0, sizeof(udpDetails));
 #ifdef VIRTUAL
-    LOG(logINFO, ("This is a VIRTUAL detector\n"));
     udpDetails[0].srcip = LOCALHOSTIP_INT;
     udpDetails[0].srcip2 = LOCALHOSTIP_INT;
 #endif
@@ -3849,27 +3848,14 @@ int power_chip(int file_des) {
 #if defined(MYTHEN3D) || defined(GOTTHARD2D)
         // check only when powering on
         if (arg != -1 && arg != 0) {
-            if (checkModuleFlag) {
-                int type_ret = checkDetectorType();
-                if (type_ret == -1) {
-                    ret = FAIL;
-                    sprintf(mess, "Could not power on chip. Could not open "
-                                  "file to get type of module attached.\n");
-                    LOG(logERROR, (mess));
-                } else if (type_ret == -2) {
-                    ret = FAIL;
-                    sprintf(mess,
-                            "Could not power on chip. No module attached!\n");
-                    LOG(logERROR, (mess));
-                } else if (type_ret == FAIL) {
-                    ret = FAIL;
-                    sprintf(mess, "Could not power on chip. Wrong module "
-                                  "attached!\n");
-                    LOG(logERROR, (mess));
-                }
+            if (!checkModuleFlag) {
+                LOG(logINFOBLUE,
+                    ("In No-Module mode: Ignoring module type. Continuing.\n"));
             } else {
-                LOG(logINFOBLUE, ("In No-Module mode: Ignoring module "
-                                  "type. Continuing.\n"));
+                ret = checkDetectorType(mess);
+                if (ret == FAIL) {
+                    LOG(logERROR, ("Could not power on chip.\n"));
+                }
             }
         }
 #endif
@@ -8270,7 +8256,7 @@ int set_master(int file_des) {
         return printSocketReadError();
     LOG(logDEBUG1, ("Setting master: %u\n", (int)arg));
 
-#ifndef EIGERD
+#if !defined(EIGERD) && !defined(GOTTHARD2D)
     functionNotImplemented();
 #else
     // only set
diff --git a/slsDetectorSoftware/include/sls/Detector.h b/slsDetectorSoftware/include/sls/Detector.h
index cc566adb4..9e3cb65f7 100644
--- a/slsDetectorSoftware/include/sls/Detector.h
+++ b/slsDetectorSoftware/include/sls/Detector.h
@@ -197,10 +197,11 @@ class Detector {
      */
     void setFlipRows(bool value, Positions pos = {});
 
-    /** [Eiger][Mythen3][Gotthard1] via stop server **/
+    /** [Eiger][Mythen3][Gotthard1][Gotthard2] via stop server **/
     Result<bool> getMaster(Positions pos = {}) const;
 
-    /** [Eiger] Set half module to master and the others to slaves */
+    /** [Eiger][Gotthard2] Set (half) module to master and the other(s) to
+     * slaves */
     void setMaster(bool value, int pos);
 
     Result<bool> isVirtualDetectorServer(Positions pos = {}) const;
diff --git a/slsDetectorSoftware/src/CmdProxy.h b/slsDetectorSoftware/src/CmdProxy.h
index f1476db99..1a0d1ddd9 100644
--- a/slsDetectorSoftware/src/CmdProxy.h
+++ b/slsDetectorSoftware/src/CmdProxy.h
@@ -1298,9 +1298,9 @@ class CmdProxy {
 
     INTEGER_COMMAND_VEC_ID_GET(
         master, getMaster, setMaster, StringTo<int>,
-        "[0, 1]\n\t[Eiger] Sets half module to master and "
-        "others to slaves.\n\t[Gotthard][Gotthard2][Mythen3][Eiger] "
-        "Gets if the current module/ half module is master.");
+        "[0, 1]\n\t[Eiger][Gotthard2] Sets (half) module to master and "
+        "other(s) to slaves.\n\t[Gotthard][Gotthard2][Mythen3][Eiger] "
+        "Gets if the current (half) module is master.");
 
     /* acquisition parameters */
 
diff --git a/slsDetectorSoftware/tests/test-CmdProxy.cpp b/slsDetectorSoftware/tests/test-CmdProxy.cpp
index 703c54858..7db7d699e 100644
--- a/slsDetectorSoftware/tests/test-CmdProxy.cpp
+++ b/slsDetectorSoftware/tests/test-CmdProxy.cpp
@@ -586,7 +586,7 @@ TEST_CASE("master", "[.cmd]") {
     if (det_type == defs::EIGER || det_type == defs::MYTHEN3 ||
         det_type == defs::GOTTHARD || det_type == defs::GOTTHARD2) {
         REQUIRE_NOTHROW(proxy.Call("master", {}, -1, GET));
-        if (det_type == defs::EIGER) {
+        if (det_type == defs::EIGER || det_type == defs::GOTTHARD2) {
             // get previous master
             int prevMaster = 0;
             {
diff --git a/slsSupportLib/include/sls/versionAPI.h b/slsSupportLib/include/sls/versionAPI.h
index 5e4aaba1a..412f62cfc 100644
--- a/slsSupportLib/include/sls/versionAPI.h
+++ b/slsSupportLib/include/sls/versionAPI.h
@@ -5,10 +5,10 @@
 #define APILIB       0x220609
 #define APIRECEIVER  0x220609
 #define APIGUI       0x220609
-#define APICTB       0x220714
-#define APIGOTTHARD  0x220714
-#define APIJUNGFRAU  0x220714
-#define APIMYTHEN3   0x220714
-#define APIMOENCH    0x220714
-#define APIEIGER     0x220714
-#define APIGOTTHARD2 0x220811
+#define APICTB 0x220816
+#define APIGOTTHARD 0x220816
+#define APIGOTTHARD2 0x220816
+#define APIJUNGFRAU 0x220816
+#define APIMYTHEN3 0x220816
+#define APIMOENCH 0x220816
+#define APIEIGER 0x220816